Dosing in small tank with high demand. Please help!

[rock_lobster]

I am having difficulty with 20 gallon tank. It is loaded with SPS and has a fairly high demand for carbonate.

I dose with a 24 hour continuous peristaltic pump using 1 gallon of water that last 6-7 days at .5ml/min. In this I dose sodium carbonate 1 tsp. I've noticed my alkalinity is becoming less and less stable as the tank has become more mature.

I plotted alkalinity in the tank for 6 days:

I started with an Alkalinity of 7.1 and refilled my doser with 1 gallon and 1tsp of sodium carbonate. The next day it spiked up to 7.85 and then on the second day up to 8.3, On the third day it went down to 8.1, 4th day 7.8, 5th day 7.5 and 6th day 7.1. The pump has been running continuously at .5ml per minute at the exact same rate and the container is nearly empty on the 6th day with just a small amount left.

The livestock shows no issues but as the demand is still increasing, Im not sure how I can adjust the dosing regimen or how to prevent that initial spike.

All other parameters are within normal limits.
Magnesium 1300
pH 7.9-8.4
Ca 420

Water changes done monthly and not during this testing period. Also the water level has been maintained with RODI water for topoff.

 

[rock_lobster]

Thought about dosing kalkwasser also but not sure if that would really help since I couldnt dose much in a 20 gallon tank.

 

[rock_lobster]

bump

 

[rock_lobster]

Guess I'm the only one with a nano sps...

 

[Sm51498]

Are you testing the same time each day? Your demand and consumption will not be constant throughout the day so it stands to reason your kh would swing. Your alk is only swinging within 1 degree of kh off of the mean. Which it's certainly not a bad idea to try for greater consistency but it may not be necessary or possible.

 

[rock_lobster]

Yes I do test at the same time approx 6pm. I guess the main issue is the initial spike I get. It's been getting larger and larger as I need to keep increasing the amount of carbonate. Anyone have issues with an initial spike on dosing?

Are you testing the same time each day? Your demand and consumption will not be constant throughout the day so it stands to reason your kh would swing. Your alk is only swinging within 1 degree of kh off of the mean. Which it's certainly not a bad idea to try for greater consistency but it may not be necessary or possible.

 

[Sm51498]

That is puzzling. You would think that wouldn't happen. It's too bad it's a constant pump, otherwise you could set it on a schedule to slowly ramp up.

I wouldn't be terribly worried about it myself, as it doesn't seem to be having a negative effect. I don't know what you can do here.

 

[rock_lobster]

That is puzzling. You would think that wouldn't happen. It's too bad it's a constant pump, otherwise you could set it on a schedule to slowly ramp up.

I wouldn't be terribly worried about it myself, as it doesn't seem to be having a negative effect. I don't know what you can do here.

I guess I forgot to mention that it does have some effect on the zoas and shrooms that I have. The spike causes them to close up a little for a day or 2 then return to normal. The main issue is coming soon when I have to dose more to keep it above 7.1 at the end of the 6 day period then the spike would get even larger.

 

[Sm51498]

Well, either your uptake is super uneven or your input is or both. How reliable is your dosing pump here? I wonder if a fresh solution of sodium bicarbonate is more potent than after it sits? I don't have the answer here unfortunately.

 

[rock_lobster]

The pump I have is lab grade very accurate. That's what I'm thinking that the carbonate solution is more potent for the first day then the falls off. or else the solution is more concentrated at the bottom of the container. I may try a stirrer or sealed container though never hear of those being needed for carbonate.

Well, either your uptake is super uneven or your input is or both. How reliable is your dosing pump here? I wonder if a fresh solution of sodium bicarbonate is more potent than after it sits? I don't have the answer here unfortunately.

 

[Bbaz123456]

Can you measure the exact amount being dosed each day? Even though it is a lab grade pump, it is still easier for the pump to pump out of a full jug than a "less full jug"- the lower the level gets, the harder it is to pull up.
It may not even be noticeable by just eyeballing.

 

[rock_lobster]

Can you measure the exact amount being dosed each day? Even though it is a lab grade pump, it is still easier for the pump to pump out of a full jug than a "less full jug"- the lower the level gets, the harder it is to pull up.
It may not even be noticeable by just eyeballing.

good idea I will check that now since I just refilled my jugs and again towards the end.

 

[twilliard]

Agreed, inconsistent amounts being dosed.

 

[rock_lobster]

Its possible, but I use an ismatec regloflow lab pump that can dose down to .003 ml per min continuously. They cost over $2,000.

 

[twilliard]

I was more leaning to the idea that what you are mixing is not staying in solution.

 

[rock_lobster]

I was more leaning to the idea that what you are mixing is not staying in solution.

I looked into that and it seems Soda ash has a very high solubility. It would take over 100 tsp to saturate a 1 gallon solution.

 

[Tahoe61]

I am having difficulty with 20 gallon tank. It is loaded with SPS and has a fairly high demand for carbonate.

I dose with a 24 hour continuous peristaltic pump using 1 gallon of water that last 6-7 days at .5ml/min. In this I dose sodium carbonate 1 tsp. I've noticed my alkalinity is becoming less and less stable as the tank has become more mature.

I plotted alkalinity in the tank for 6 days:

I started with an Alkalinity of 7.1 and refilled my doser with 1 gallon and 1tsp of sodium carbonate. The next day it spiked up to 7.85 and then on the second day up to 8.3, On the third day it went down to 8.1, 4th day 7.8, 5th day 7.5 and 6th day 7.1. The pump has been running continuously at .5ml per minute at the exact same rate and the container is nearly empty on the 6th day with just a small amount left.

The livestock shows no issues but as the demand is still increasing, Im not sure how I can adjust the dosing regimen or how to prevent that initial spike.

All other parameters are within normal limits.
Magnesium 1300
pH 7.9-8.4
Ca 420

Water changes done monthly and not during this testing period. Also the water level has been maintained with RODI water for topoff.

Nice detail to initial post.

What is your testing type method for alk?

My preference for a sps dominate nano is Kalkwasser, I have never seen any significant swings when used in the top off as long as you take the time to start with a lower concentration of kalk to ro and then ramp up slowly to reach the desired volume.

 

[rock_lobster]

Nice detail to initial post.

What is your testing type method for alk?

My preference for a sps dominate nano is Kalkwasser, I have never seen any significant swings when used in the top off as long as you take the time to start with a lower concentration of kalk to ro and then ramp up slowly to reach the desired volume.

Thanks, I use the salifert alkalinity kit. Its accurate and measures the standard solution perfectly.

I thought about using kalkwasser as a supplement to my current dosing regimen. I know I've tried it in the past and had issues with not being able to dose enough saturated kalk solution to keep up with the alkalinity demand (2 tsps per gallon max). The tank only evaporates about 2 gallons a week. So I could add a max of 2 gallons of saturated kalk or 4 tsps.

I may be able to use it in combination with the carbonate or I would probably have to switch to bicarb to prevent the pH from spiking.

 

[Tahoe61]

Kalkwasser has always been my go to in my nanos with supplemental dosing of parts A/B. My nanos typically require 1/4 gallon per day in replacement water so it works well with for me. My alk typically stays within 8-9. It just works for me.

 

[rock_lobster]

Kalkwasser has always been my go to in my nanos with supplemental dosing of parts A/B. My nanos typically require 1/4 gallon per day in replacement water so it works well with for me. My alk typically stays within 8-9. It just works for me.

Thanks! Ill give the kalk a try with the 2 part.