Side-by-side mixing station question

[Special_K]

I've been researching my options for mixing station, and one question always haunts me: After pumping saltwater out for a water change, we need to pump RO water from RO tank into the salty tank. But, there is still a little saltwater in the pipes, and it will be mixed with new RO water, so every time the salty tank will have a little saltwater to begin with, right? Will this affect the amount of salt we put in?

 

[McAllyn]

This is a problem I ran into with my mixing station, however, after the first batch was made and pumped into the tank, I just added the appropriate amount of RODI to the leftover saltwater then slowly added salt and tested repeatedly until I hit the right number. The amount of leftover water never changes, so the amount of salt I need to add never changes either.

 

[Rick.45cal]

I ran two independent lines with two independent pumps.

 

[Special_K]

This is a problem I ran into with my mixing station, however, after the first batch was made and pumped into the tank, I just added the appropriate amount of RODI to the leftover saltwater then slowly added salt and tested repeatedly until I hit the right number. The amount of leftover water never changes, so the amount of salt I need to add never changes either.

Hmmmm.... That doesn't sound very consistent. What if I have to wash the saltwater tank? The next mix will be like a chemical lab class?

 

[Special_K]

I ran two independent lines with two independent pumps.

That's sounds better. One pump to transfer water from RO tank to saltwater tank, one pump to do the mixing and water changing, right? That being said, will it be more efficient stacking two tanks top-bottom? Top RO tank can fill bottom saltwater tank using gravity, so that we can eliminate one pump.

 

[McAllyn]

Hmmmm.... That doesn't sound very consistent. What if I have to wash the saltwater tank? The next mix will be like a chemical lab class?

It's been very consistent for me for the last year. My tank is marked for when 10 gallons has been pumped out. I mix 10 gallon batches. The leftover is roughly 1.5 gallons, but that's somewhat irrelevant since I'm using 10 gallons. For me, at 79deg, Reef Crystals mixes to 1.026 with 6 level scoops from my measuring cup. Obviously, I check it every time, and the consistency is very reliable.

When I've cleaned my mixing bucket, I still just make 10 gallons, but I don't pump all 10 gallons out of the tank. The leftover in the mixing tank is still about 1.5 gallons of 1.026. But, I rarely clean my mixing bucket, maybe twice in the past year.

Mac

 

[BlueCursor]

My RO is a 1/4" tube from my RODI unit. It takes overnight to fill, but I have no extra tube for RO.

 

[Special_K]

It's been very consistent for me for the last year. My tank is marked for when 10 gallons has been pumped out. I mix 10 gallon batches. The leftover is roughly 1.5 gallons, but that's somewhat irrelevant since I'm using 10 gallons. For me, at 79deg, Reef Crystals mixes to 1.026 with 6 level scoops from my measuring cup. Obviously, I check it every time, and the consistency is very reliable.

When I've cleaned my mixing bucket, I still just make 10 gallons, but I don't pump all 10 gallons out of the tank. The leftover in the mixing tank is still about 1.5 gallons of 1.026. But, I rarely clean my mixing bucket, maybe twice in the past year.

Mac

That sounds more reassuring. So I would think we normally make more saltwater than we need for water change, right? I have to pump that from basement to where the display tank is. The saltwater has to come back to the container when the pump's power is cut., plus the water left in the container, that's considerable amount of saltwater after the water change. Now I understand why some people install valve on the lower pluming to empty the tank. That might be a better idea for side-by-side installation.

 

[Rick.45cal]

You can do it that way, so you produce RO/DI and transfer to the saltwater mixing tank, or you can put a float switch in each container and a valve in the RO/DI line So you can fill either reservoir. I then have a freshwater line that runs to my ATO container from the DI tank, and a saltwater line that runs to the tank. There are also valves by the tanks so I can fill containers if I need to.

My saltwater reservoir also has a line running to a DOS that automatically changes water in my tank, so I basically just make saltwater every 6.25 weeks and the Apex does the rest.

By using two seperate containers I can use a very large Saltwater storage vessel (150 gallons) and a relatively small DI storage vessel (35 gallons). I also don't have to juggle liquid from one container to the other. (It's much simpler IMO).

 

[McAllyn]

Unfortunately, I'm in an apartment, so my options are limited in how far I can automate. Mine is a gravity fed system, 25g RODI container on top, 20g mixing vessel below. When I'm mixing, I turn a valve and drop 10g into the mixing vessel. It is plumbed with a pump in a circuit that mixes very well. After a reasonable amount of time mixing, there is a couple valves that form a diverter to pump it to the tank about 15ft away. I use flex hose for that.

Before I pump the new water in, I use another small pump and flex hose to pump the appropriate amount of water directly to the sink.

Not as great a system as some, but I haven't used a bucket or dripped more than a couple drops on the floor since I put the system together.

Mac

 

[Special_K]

You can do it that way, so you produce RO/DI and transfer to the saltwater mixing tank, or you can put a float switch in each container and a valve in the RO/DI line So you can fill either reservoir. I then have a freshwater line that runs to my ATO container from the DI tank, and a saltwater line that runs to the tank. There are also valves by the tanks so I can fill containers if I need to.

My saltwater reservoir also has a line running to a DOS that automatically changes water in my tank, so I basically just make saltwater every 6.25 weeks and the Apex does the rest.

By using two seperate containers I can use a very large Saltwater storage vessel (150 gallons) and a relatively small DI storage vessel (35 gallons). I also don't have to juggle liquid from one container to the other. (It's much simpler IMO).

This sounds very interesting. How big is your set up? and how much water you are changing everyday? Is the DOS reliable? I would like to learn more about your method.

 

[Special_K]

Mmmmm, the problem with Top-Bottom configuration is, it will be a pain to dump salt in the bottom tank...

 

[McAllyn]

Not when you build the shelves that support the reservoirs to accommodate that. Not like I'm putting an entire bucket of salt in at a time, just six scoops. And there's enough room for me to look down/reach into the bottom reservoir as needed.

 

[Special_K]

That's a great point! Thanks

 

[Rick.45cal]

This sounds very interesting. How big is your set up? and how much water you are changing everyday? Is the DOS reliable? I would like to learn more about your method.

My tank is a DSA 190 with about 160 gallons net water volume. I change the equivalent of 10% per week, which is about 8651.5ml a day. It's been very reliable for me so far.

I use a 35 gallon leg tank from tractor supply and a large 150 gallon reservoir for new saltwater storage. I've got my 150gallon reservoir plumbed with a Reeflo suntail (about 4000 gph) which is directed at the bottom to create a gyre within the container (It makes the entire contents form a whirlpool inside the container) to prevent any salt from sitting on the bottom when I am mixing. It works so good, all I do is fill it with RO/DI turn on the pump and dump my salt in it. I let it run for a few hours and then start testing/adjusting levels.

 

[Special_K]

Thank you for the write up. Answered many questions I have. I'm planning on a basement set up with auto water change.

 

[Rick.45cal]

I also have the saltwater reservoir plumbed with a 3/4" pvc line directly to the back of the display tank. That way I can always do a water change manually and fill the tank up without carrying any buckets. (I have a python no spill clean and fill, to siphon with). It's the best of both worlds.

 

[Seyoz]

Hmmmm.... That doesn't sound very consistent. What if I have to wash the saltwater tank? The next mix will be like a chemical lab class?

I hear you, Every night when At LFS, We would top off 200 gallon Vat. Simply under mixed salt needed, slowly adjusted after pump ran over night we with aeration. Letting Clorine burn mixture over night, buffered and adjusted afterhours if had time or adjusted hours before opened.

 

[Seyoz]

And the Reef Mix, would top off overnight and add salt and buffer hours before opened. Can't divulge exact 40 year formula, but we never had problems in our tanks or friends that used both water batches.

 

[Seyoz]

When adding to already made stock, add (1/2) what you thought. Make sure to have batch mix well with Powerhead, so not to over use salt reserve by adding too much..

After few times you will have more confidence, worst case scenario you have to pour extra money down the drain and dilute to approximate desired salinity..

Just don't buffer or declor til after salinity fixed. So don't drop pH from excess uses of each.