New Limewater Dosing

[piranhaman00]

Hello,

After much internal debate I’ve decided to try limewater (kalkwasser) dosing. I was getting sick of dosing 2 part and this should knock out 4 birds; alk, ca, ato and help pH.

System is approx 420 gallons consisting of 360 gallon DT, 60 gallon frag and 150 gallon sump.

I saturated rodi with Ca(OH)2 in a 44 gallon brute using 450 grams of lime. After settling I transferred to a secondary holding tank next to my ato tank. I set up an auto doser to dose 320mL every hour which is about 7.6L per day which is about 0.5 -0.6 dkH per day, equal to just about what the system is consuming per day. I shut off my ATOs to see how water level would be.

After two days my aquarium is actually gaining water ie. I’m dosing limewater faster than evap, even at this ‘lower’ end dose. I want to continue to dose limewater and forgo any 2 part. Any ideas?

1. The DTs have lids to actually prevent evap to allow less time making rodi, I guess that is now working against me. I could remove the lids to allow for more evap as well as benefit of light penetration and gas exchange.

2. Put fans in sump to speed evap. Tank is lit by 16 T5s so gets warm, would also help cool tank in summer.

Any other ideas?

 

[MoshJosh]

Can up the Kalk concentration by adding vinegar. I don't know the exact details of that method, but I assume Randy has info on it. Note I assume the vinegar is going to affect the pH affects.

Removing lids and adding a fan could certainly up your evaporation so may be worth a try.

 

[ReefingDreams]

Hello,

After much internal debate I’ve decided to try limewater (kalkwasser) dosing. I was getting sick of dosing 2 part and this should knock out 4 birds; alk, ca, ato and help pH.

System is approx 420 gallons consisting of 360 gallon DT, 60 gallon frag and 150 gallon sump.

I saturated rodi with Ca(OH)2 in a 44 gallon brute using 450 grams of lime. After settling I transferred to a secondary holding tank next to my ato tank. I set up an auto doser to dose 320mL every hour which is about 7.6L per day which is about 0.5 -0.6 dkH per day, equal to just about what the system is consuming per day. I shut off my ATOs to see how water level would be.

After two days my aquarium is actually gaining water ie. I’m dosing limewater faster than evap, even at this ‘lower’ end dose. I want to continue to dose limewater and forgo any 2 part. Any ideas?

1. The DTs have lids to actually prevent evap to allow less time making rodi, I guess that is now working against me. I could remove the lids to allow for more evap as well as benefit of light penetration and gas exchange.

2. Put fans in sump to speed evap. Tank is lit by 16 T5s so gets warm, would also help cool tank in summer.

Any other ideas?

Given the constraints you mentioned, you only have two options.
1) Increase evaporation to be able to dose more limewater.
2) Increase saturation point of the limewater via vinegar (minimally effective), or start to dose a limewater slurry. You'll want to do some research on that option. Telegraham has a good YouTube video on the topic. I'm currently running a very heavy slurry myself. I recommend a much lighter slurry than what I'm running since I have to blow out all dosing lines every 2 days. With less kalk this wouldn't be an issue.

 

[Garf]

minimally effective

I'm using 90mls of vinegar per gallon (soon going to 100mls) which appears to almost double it's potency.

I assume the vinegar is going to affect the pH

Yes, it does lower it a bit, but that can be a good thing.

I could remove the lids to allow for more evap as well as benefit of light penetration and gas exchange.

Sounds like a sound plan.

 

[piranhaman00]

thanks. I do not want to add vinegar as I want to maintain the high pH as well as carbon dosing in a broadcast fashion gives my cyano outbreak. Currently dosing vinegar into a anaerobic reactor for denitrification.

 

[Randy Holmes-Farley]

What happened to alkalinity in those 2 days?

 

[piranhaman00]

What happened to alkalinity in those 2 days?

It raised as expected and stabilized my alk. Calculations were correct. However with water level increasing I am forced to back off.

 

[ReefingDreams]

I'm using 90mls of vinegar per gallon (soon going to 100mls) which appears to almost double it's potency.

Yes, it does lower it a bit, but that can be a good thing.

Sounds like a sound plan.

Sorry, sbould have added context on that one. "Minimally effective" as compared to the second part of the post, which was slurry. Also, the vinegar would cause a PH hit of the solution (not sure if it would be enough at double the normal saturation point to be impactful overall or not), and I'd be a bit concerned about the carbon this would add and the potential hit to nutrients.

I may test out the vinegar option on my own to see how it does. Just a limited test to gain some knowledge with this solution. Thanks for sharing!

 

[Randy Holmes-Farley]

It raised as expected and stabilized my alk. Calculations were correct. However with water level increasing I am forced to back off.

Ok, so if increasing evaporation is not going to work, then you may be better off using a different method, or taking the pH high and adding some vinegar to the limewater/kalkwasser. This evaporation limitation is the primary issue with limewater.

 

[piranhaman00]

Ok, so if increasing evaporation is not going to work, then you may be better off using a different method, or taking the pH high and adding some vinegar to the limewater/kalkwasser. This evaporation limitation is the primary issue with limewater.

I am going to remove the hoods from the frag tank and blow a large fan over the sump. I really want limewater to work so I can stop 2 part. Also having pH boost is great!

 

[ReefingDreams]

I am going to remove the hoods from the frag tank and blow a large fan over the sump. I really want limewater to work so I can stop 2 part. Also having pH boost is great!

This is the way! Good luck.

 

[Randy Holmes-Farley]

I am going to remove the hoods from the frag tank and blow a large fan over the sump. I really want limewater to work so I can stop 2 part. Also having pH boost is great!

I understand. It is my preferred method too. But a DIY two part can give an identical pH boost.

 

[piranhaman00]

I understand. It is my preferred method too. But a DIY two part can give an identical pH boost.

Yes I also dose sodium hydroxide. May have to use both but we shall see how this experiment goes

 

[Randy Holmes-Farley]

Yes I also dose sodium hydroxide. May have to use both but we shall see how this experiment goes

OK, keep us updated.

 

[piranhaman00]

Update:

Removed lids from frag tank , helped a lot. However the increase in pH resulted in increased alk consumption which led to more dosing needed…good problem.

Added fan to sump to cause more evap. Works very well but also cause problems with humidity , heaters on more ect. However, I am fine with this for now if I keep seeing these results.

Summary:

pH increased from 7.85-8.20 to 8.05-8.30. Caps around 8.30 because I stop the doser at 8.30 for now.

Alk consumption increased from 0.4dkh to about 0.75 dkh. I’m sure it will continue to increase.

Dosing out of a 40 gallon brute. I saturate in a separate brute and then pump here. Still lots of settled kalk.

Dosing using a Kamoer pump, greatly reduces chances of sucking up sludge. Set dosing line to eliminate risk.

 

[Randy Holmes-Farley]

Sounds good!