DIY Frozen Food Feeder

[aaron23]

Good question...Most likely there is some... but I keep the temperature around 30 F which would slows down the process...I change the food and rinse out the container every 5 days when in use ... no evidence of ammonia build up as of yet ... I am sure the food does not have the nutrition a fresh prepared batch does but maybe better then nothing

Definitely agree, at the moment I've made my fish food into ice cubes and I use ROwater to defrost the cube of food if I don't use the entire amount because of all the bacteria etc that's in the saltwater that can speed up the food spoilage. Maybe if used with RO water it may keep the food more clean? Just a thought also the tank water that suspends the food is at ~80 degrees so that should start the breakdown of food sooner

 

[Paul B]

Nice!

@Paul B also has a design for one that's pretty nice too....designed for in-tank use. A bit simpler too, maybe.

It's in his book "The Avante Garde Marine Aquarist" but I bet he's posted it online somewhere before too.

Yes, but Rick's is much better because it is automatic and it keeps the food cold.

 

[mcarroll]

Simple is not always better, and better is not always more simple?

They are quite different feeders...only the end result of fish being fed is the the same.

Different enough that I could see both being useful, depending on your scenario.

 

[Rick Mathew]

Definitely agree, at the moment I've made my fish food into ice cubes and I use ROwater to defrost the cube of food if I don't use the entire amount because of all the bacteria etc that's in the saltwater that can speed up the food spoilage. Maybe if used with RO water it may keep the food more clean? Just a thought also the tank water that suspends the food is at ~80 degrees so that should start the breakdown of food sooner

I believe you're correct about the RODI vs Seawater statement...After experiment with both I selected the seawater because I can keep it colder without freezing up. I can actually keep it as low as 30 F because the sea water does not freeze until 28 F...When I back flush from the 80 F tank about 90 ml into 350 ml of 30F water it raises the temp about 2-3 F...in 25 min or so it is back to 30...I also have experiment with adding a small amount of ammonia scavenger to slow the process but the results are still out as to whether in makes a difference...I have a SENEYE REEF that monitors the ammonia level ever 5 min or so which I watched closely during the testing phase...It did not appear to have an impact on the level. My main concern is how much of the nutritional value is lost due to the breakdown of the bacteria from the tank...I am not sure how to measure that. I am still looking for information on this topic. That being said I supplement with high protein pellets once a day and do not use the feeder all the time...just when my week gets crazy and I need some flexibility. Thanks for the input.

 

[Rick Mathew]

Simple is not always better, and better is not always more simple?

They are quite different feeders...only the end result of fish being fed is the the same.

Different enough that I could see both being useful, depending on your scenario.

Spot on!

 

[DBR_Reef]

Nice write up! I just made a refrigerated food dispenser myself- it is definitely a worthwhile project. I'll have to do a write up, as the design is different, much cheaper, and the food last a long time- but that will have to wait until after Christmas. I will say that having taste tested thawed frozen mysis refrigerated at 32 degrees (which is warmer, but not by much), by day three it tastes off, and at day 5 it was foul- it didn't smell bad, but it sure tasted off. And I used alcohol to disinfect the storage container. I would not use tank ammonia as a guide for food spoilage- any cycled tank will quickly process any extra ammonia, and even if it didn't, if you are dosing 40ml into a 200 gallon system, you would need to be dosing food with ammonia concentrations .1-.01 that of household ammonia in order to detect the addition, which you will never have. I will note that you are using salt water for the thaw water, which may be acting as a slight preservative, but I would at least check it. Every batch of mysis (or other food) will be different on it's spoilage time, as each batch starts out with a different amount of bacteria in the product, but maybe reduce storage time by a day and sanitize the container between refills as a precaution

 

[Rick Mathew]

Nice write up! I just made a refrigerated food dispenser myself- it is definitely a worthwhile project. I'll have to do a write up, as the design is different, much cheaper, and the food last a long time- but that will have to wait until after Christmas. I will say that having taste tested thawed frozen mysis refrigerated at 32 degrees (which is warmer, but not by much), by day three it tastes off, a at day 5 it was foul- it didn't smell bad, but it sure tasted off. And I used alcohol to disinfect the srage tainer. I would not use tank ammonia as a guide for food spoilage- any cycled tank will quickly process any extra ammonia, and even if it didn't, if you are dosing 40ml into a 200 gallon system, you would need to be dosing food with ammonia concentrations .1-.01 that of household ammonia in order to detect the addition, which you will never have. I will note that you are using salt water for the thaw water, which may be acting as a slight preservative, but I would at least check it. Every batch of mysis (or other food) will be different on it's spoilage time, as each batch starts out with a different amount of bacteria in the product, but maybe reduce storage time by a day and sanitize the container between refills as a precaution

Wow a taste test ....never thought of that....not sure I am up for that...Thanks for the good ideas Your point is well taken on the delution factor...I like your idea of sanitizing the container....Very much looking forward to your write up and thank you for your insights, they are helpful

 

[ebushrow]

How long does this get used before it needs to be refilled? Maybe I missed it above....and one other question....doesn't the food go bad before it is used up? I thought that the thawed food would break down quickly...

but moreover, this is an awesome idea!!!

 

[Rick Mathew]

How long does this get used before it needs to be refilled? Maybe I missed it above....and one other question....doesn't the food go bad before it is used up? I thought that the thawed food would break down quickly...

but moreover, this is an awesome idea!!!

Good questions....I actually refill every 3-4 days sometimes 5...I empty out the container...rinse it clean and add a new batch of food...as for the food going bad...Most likely there is some degradation... but I keep the temperature around 30 F which would slows down the process... I am sure the food does not have the nutrition a freshly prepared batch does but maybe better than nothing. I am currently working on a quantitative method to look into this very question

 

[bozo]

I think I would remove the tubing from the tank water just to prevent the possibility of back-siphoning.

(I don't think having is submerged does anything good, does it?)

I'm not sure if it's possible to back siphon on peristaltic pumps.

But I'd do it just to be safe lol

 

[Rick Mathew]

I'm not sure if it's possible to back siphon on peristaltic pumps.

But I'd do it just to be safe lol

I am actually not so worried about back siphon as much as I am cautious about the DOS malfunctioning on the back fill cycle and pumping all of the water in the tank out to below the tube exit point...Hasn't happened yet but being very familiar with "Murphy's Laws" I am sure if it would happen it would be while I was out of town and my wife would have to deal with it...not a happy thought!

 

[mcarroll]

Ah....the double-edged sword of automation.

 

[Rick Mathew]

Ah....the double-edged sword of automation.

For sure don't know which side of the sword is sharper...I only know from experience that the only time technology fails is when you really need it!...in a hurry to print something...printer decides to do it's calibrating "thing"...ready to make a presentation... projector bulb burns out....and on and on it goes ):

 

[klp]

Wonderful article and loved the ingenuity.

I am actually not so worried about back siphon as much as I am cautious about the DOS malfunctioning on the back fill cycle and pumping all of the water in the tank out to below the tube exit point...Hasn't happened yet but being very familiar with "Murphy's Laws" I am sure if it would happen it would be while I was out of town and my wife would have to deal with it...not a happy thought!

Wonderful article and loved the ingenuity!
Having a hard time picturing from the drawings how you would overflow from the exit point which if I read the drawings correctly is coming from your fridge. Most airline valves have a backflow preventer so I am not sure where it would overflow from unless from a leaking DOS. Could you give a little more detail as to your concerns for us dummies? Once again great job!

 

[Rick Mathew]

Wonderful article and loved the ingenuity.

Wonderful article and loved the ingenuity!
Having a hard time picturing from the drawings how you would overflow from the exit point which if I read the drawings correctly is coming from your fridge. Most airline valves have a backflow preventer so I am not sure where it would overflow from unless from a leaking DOS. Could you give a little more detail as to your concerns for us dummies? Once again great job!

No problem...So here is how the feed cycle works...

1) Apex DOS pumps 20mL from the tank into the food container to flush out the line ---At this point if the DOS (Apex) were to fail and continue running it would overflow the food container and pump water out of the tank until the exit tube (the one in the tank) is out of the water....approx 10-15 Gal

2) Apex DOS then pumps 90mL from the food container into the tank to feed the fish...if the DOS were to fail here and continue running the worst case would be I would have a massive overfeeding which would be much easier to deal with than 15 gal of water in my family room

3) The Apex program I wrote then waits for 15 min and then begins pumping 70mL from the tank into the food container to back flush the lines to prevent any food from remaining in the lines and going bad--Here again at this point if the DOS (Apex) were to fail and continue running it would overflow the food container and pump water out of the tank until the exit tube (the one in the tank) is out of the water....approx 10-15 Gal

4) DOS shuts down and waits for the next feeding cycle to come due...which in my case is 24 hours

Hope this helps

Rick

 

[Rick Mathew]

I posted this as seperate post but thought I would include it here for those of you who asked the question about food stability

Many of you have asked me a very good question in my DIY post of “The Frozen Food Feeder” (Here is the link https://www.reef2reef.com/threads/diy-frozen-food-feeder.279232/ ) about the stability of the food over time….will it go bad….will it break down. You got me to thinking. Are my assumptions correct or am I feeding my fish and corals “bad” food? I could not find any relevant posts that had any data, just mostly anecdotal observations. (Some of you might be able to point me in the right direction).So I decided to make some phone calls and do some digging for some relative data on the stability of the food at different temperatures. My sister-in-law is a clinical pathologist so I reached out to her. She pointed me in the direction of the frozen food industry. Her Job consisted of a lot of different kinds of tissue preservation so she had a lot of insight into the matter. Without troubling you with all of the details, I found these two articles very helpful in understanding the issue. (If math scares you you may not want to look at these )

http://www.fao.org/docrep/V7180E/V7180e07.htm

https://seagrant.uaf.edu/lib/asg/30/ASG-30.pdf

From these two articles I calculated what is referred to as “Equivalent Days on Ice” time at my storage temperature of 30⁰-31⁰ F and subtracted that from the “Maximum Shelf Life of Shrimp at 32⁰ F on Ice”( 5 Days) to find my “Remaining Shelf Life” . This shelf life is based on fitness for human consumption, so I had to make the assumption that it would hold true for my fish…not sure this is totally valid.

I found my Remaining Shelf Life was in a safe range for usage given 5 days is the maximum time I keep a batch in the feeder. My calculations give me about 12-24 hours of extra shelf life at my holding temperatures. She (my sister-in-law) also recommended an experiment that I can do to validate the assumptions and calculations, which I will do later.

I have read a number of posts on various websites that say that people thaw the frozen food and then store it in the frig for over a week. The average temperature of a refrigerator is between 32 to 40⁰ F. That means the food is approximately 2-10 days past its useful shelf life. When you read the articles you will see that the changes in remaining shelf life are not linear with temperature which means the spoilage is two times as fast as you go from 32⁰-40⁰ F

Well that’s probably enough for now. I appreciate all of you questions. It motivated me to dig into the data. Not sure it is 100% applicable but it is better than what I had before and I am still in the process of exploring the subject…Will keep you posted as I do my experiment and a bit more digging, but at least it is a move in the right direction.

Thanks

Rick

PS If any of you can point me to additional information that could be used it would be appreciated.

 

[Rick Mathew]

You don't have issues with bacteria from tank water breaking down the frozen food?

Here is an update to your question

Many of you have asked me a very good question in my DIY post of “The Frozen Food Feeder” (Here is the link https://www.reef2reef.com/threads/diy-frozen-food-feeder.279232/ ) about the stability of the food over time….will it go bad….will it break down. You got me to thinking. Are my assumptions correct or am I feeding my fish and corals “bad” food? I could not find any relevant posts that had any data, just mostly anecdotal observations. (Some of you might be able to point me in the right direction).So I decided to make some phone calls and do some digging for some relative data on the stability of the food at different temperatures. My sister-in-law is a clinical pathologist so I reached out to her. She pointed me in the direction of the frozen food industry. Her Job consisted of a lot of different kinds of tissue preservation so she had a lot of insight into the matter. Without troubling you with all of the details, I found these two articles very helpful in understanding the issue. (If math scares you you may not want to look at these )

http://www.fao.org/docrep/V7180E/V7180e07.htm

https://seagrant.uaf.edu/lib/asg/30/ASG-30.pdf

From these two articles I calculated what is referred to as “Equivalent Days on Ice” time at my storage temperature of 30⁰-31⁰ F and subtracted that from the “Maximum Shelf Life of Shrimp at 32⁰ F on Ice”( 5 Days) to find my “Remaining Shelf Life” . This shelf life is based on fitness for human consumption, so I had to make the assumption that it would hold true for my fish…not sure this is totally valid.

I found my Remaining Shelf Life was in a safe range for usage given 5 days is the maximum time I keep a batch in the feeder. My calculations give me about 12-24 hours of extra shelf life at my holding temperatures. She (my sister-in-law) also recommended an experiment that I can do to validate the assumptions and calculations, which I will do later.

I have read a number of posts on various websites that say that people thaw the frozen food and then store it in the frig for over a week. The average temperature of a refrigerator is between 32 to 40⁰ F. That means the food is approximately 2-10 days past its useful shelf life. When you read the articles you will see that the changes in remaining shelf life are not linear with temperature which means the spoilage is two times as fast as you go from 32⁰-40⁰ F

Well that’s probably enough for now. I appreciate all of you questions. It motivated me to dig into the data. Not sure it is 100% applicable but it is better than what I had before and I am still in the process of exploring the subject…Will keep you posted as I do my experiment and a bit more digging, but at least it is a move in the right direction.

Thanks

Rick

PS If any of you can point me to additional information that could be used it would be appreciated.

 

[Rick Mathew]

Very cool nice work. I was wondering if the saltwater suspending the food after each feeding will end up degrading and break down the food/ food spoilage?

Thanks @Rick Mathew

Here is an update to your question

Many of you have asked me a very good question in my DIY post of “The Frozen Food Feeder” (Here is the link https://www.reef2reef.com/threads/diy-frozen-food-feeder.279232/ ) about the stability of the food over time….will it go bad….will it break down. You got me to thinking. Are my assumptions correct or am I feeding my fish and corals “bad” food? I could not find any relevant posts that had any data, just mostly anecdotal observations. (Some of you might be able to point me in the right direction).So I decided to make some phone calls and do some digging for some relative data on the stability of the food at different temperatures. My sister-in-law is a clinical pathologist so I reached out to her. She pointed me in the direction of the frozen food industry. Her Job consisted of a lot of different kinds of tissue preservation so she had a lot of insight into the matter. Without troubling you with all of the details, I found these two articles very helpful in understanding the issue. (If math scares you you may not want to look at these )

http://www.fao.org/docrep/V7180E/V7180e07.htm

https://seagrant.uaf.edu/lib/asg/30/ASG-30.pdf

From these two articles I calculated what is referred to as “Equivalent Days on Ice” time at my storage temperature of 30⁰-31⁰ F and subtracted that from the “Maximum Shelf Life of Shrimp at 32⁰ F on Ice”( 5 Days) to find my “Remaining Shelf Life” . This shelf life is based on fitness for human consumption, so I had to make the assumption that it would hold true for my fish…not sure this is totally valid.

I found my Remaining Shelf Life was in a safe range for usage given 5 days is the maximum time I keep a batch in the feeder. My calculations give me about 12-24 hours of extra shelf life at my holding temperatures. She (my sister-in-law) also recommended an experiment that I can do to validate the assumptions and calculations, which I will do later.

I have read a number of posts on various websites that say that people thaw the frozen food and then store it in the frig for over a week. The average temperature of a refrigerator is between 32 to 40⁰ F. That means the food is approximately 2-10 days past its useful shelf life. When you read the articles you will see that the changes in remaining shelf life are not linear with temperature which means the spoilage is two times as fast as you go from 32⁰-40⁰ F

Well that’s probably enough for now. I appreciate all of you questions. It motivated me to dig into the data. Not sure it is 100% applicable but it is better than what I had before and I am still in the process of exploring the subject…Will keep you posted as I do my experiment and a bit more digging, but at least it is a move in the right direction.

Thanks

Rick

PS If any of you can point me to additional information that could be used it would be appreciated.

 

[troiusmaximus]

For those of us with no Neptune controller or DOS pumping system, I was wondering if a regular two or four pump doser like a Jaebo could approximate the function of reverse pumping by using one pump (1) to extract food from the container and a second pump (2) to pump water from the display. I would have a junction close to the output of the feeding tube so that the suction of water from the tank would back flush food back into the container. I could have a sealed lid on my food container so it wouldn't fill beyond capacity. The output of (2) might go into the sump?

 

[Rick Mathew]

For those of us with no Neptune controller or DOS pumping system, I was wondering if a regular two or four pump doser like a Jaebo could approximate the function of reverse pumping by using one pump (1) to extract food from the container and a second pump (2) to pump water from the display. I would have a junction close to the output of the feeding tube so that the suction of water from the tank would back flush food back into the container. I could have a sealed lid on my food container so it wouldn't fill beyond capacity. The output of (2) might go into the sump?

Actually I see no reason why not...I considerd 4 factors important

1) Don't let food remain outside ot the frig---Feeding tube outside of refrigerator needed to be clean as possible to prevent the food from rotting----Thus my back purges

2) Food delivery need to be dependable and a relatively consistent amount...For me this required a larger diameter tubing running from the feeder to the tank. The smaller diameter tubing would clog...with some experimenting I found PVC tubing with Outside Diameter if 1/4" and Inside Diameter if .17" worked well (from ACE hardware...one of my favorite places).

3) Because I use a mix of foods I wanted to make sure the food delivered was a good blend of the actual mixture....thus the air stir.

For 2 and 3 I had to do a bit tweaking to get it right...which I determined by running a cycle, look at what it delivered and compare it to a sample I mixed up by hand...Visual observation

4) I wanted to assure the "gadget" did not dump water all over my house, thus the balance between the amount delivered from the feeder...in my case 90mL, had to balance with the purge(back feed) volume 90Ml ...this also keeps the volume in the feed container at a constant level and helps keep the distribution by the air mix relatively constant. The float switch provides me a measure of comfort that if for some unforeseen reason the APEX or Dosing pump malfunctions I will not flood my house.

So I would say give it a try ..."nothing ventured nothing gained"

I monitored my setup feed cycle for 2 weeks...I physically watched the entire cycle to be sure it worked. As I saw issued I made adjustments to resolve them (air tube placement as an example)...let me know how it goes

Thanks for the question

Rick