Conversion of Two-Part to Limewater

-Logzor · Nov 4, 2014

My system consists of a 150 gallon display with a sump volume of approximately 30 gallons. Total combined is going to be around 180 gallons.

I have a heavily populated SPS reef tank supplemented by two-part dosing (Randy's High-Strength Recipes as sold by Bulk Reef Supply). For the Alkalinity I use 2 cups per gallon of RO/DI and for the calcium I used 2.5 cups per gallon of RO/DI.

In addition to two-part I also have dosing pump setup with saturated limewater. I don't use vinegar to increase the concentration, it's only RO/DI water and kalkwasser (as sold by Bulk Reef Supply).

Right now I dose 230 mL a day of alkalinity part and 220 mL a day of the calcium part and 140 mL a day of the limewater part.

Is there a simple conversion for switching a portion of my two-part to limewater dosing? My goal is to increase my pH but also have less impact on my salinity over time. Keep in mind I'm not using a kalk reactor, I'm only dosing limewater via dosing pump.

zemuss · Nov 4, 2014

Logzor,

Have you considered replacing the dosing of the two part with a Calcium reactor and supplementing with the lime water dosing? Might be cheaper.. WIth a system this big two part might start to get expensive.

Randy Holmes-Farley · Nov 4, 2014

The limewater is roughly 45 times less potent than the two part.

So to stop 20 mL of each part of the two part needs roughly 900 mL of limewater.

That said, there is never a 1:1 swap when changing additives that also change pH, since the pH change itself alters demand in the tank.

zemuss · Nov 4, 2014

Randy,

Would you recommend a calcium reactor at this point?

-Logzor · Nov 4, 2014

zemuss said:
Logzor,

Have you considered replacing the dosing of the two part with a Calcium reactor and supplementing with the lime water dosing? Might be cheaper.. WIth a system this big two part might start to get expensive.

I have considered this but have decided that it's probably not the best option at this point. I've invested significant resources in my dosing pumps as well as have learned from my mistakes with this system. I believe the security of the system and lessons learned outweighs the learning curve, cost, and risks associated with moving to a calcium reactor. I might like to try this on my frag system so I can learn more about these systems. When I upgrade and demand for supplementation reaches epic levels, I should probably have some experience with reactors so I can make the switch.

Randy Holmes-Farley said:
The limewater is roughly 45 times less potent than the two part.

So to stop 20 mL of each part of the two part needs roughly 900 mL of limewater.

That said, there is never a 1:1 swap when changing additives that also change pH, since the pH change itself alters demand in the tank.

I had no idea it would take that much limewater to equal the two-part. So the 140 mL that I'm adding has almost no impact?

Are you saying that the 230 mL I'm dosing of two-part is equal to 10,000 mL of limewater? Is this doubled to include the calcium that I'm dosing as well? I'm not sure if you mean the limewater is 45 times less potent than the combined or individual two-part.

What kind of change in pH are we talking if I made this transition. Theoretically I could do it but I would need to move from 5 gallon dosing buckets up to 10 gallon dosing buckets!

zemuss · Nov 4, 2014

Is the Limewater part of your ATO system? Maybe this is where having limewater inline with an ato is better than as a dose parameter?

Randy Holmes-Farley · Nov 4, 2014

zemuss said:
Randy,

Would you recommend a calcium reactor at this point?

It is a fine choice, but is an upfront expense.

A two part can do the job, as long as you watch salinity.

Randy Holmes-Farley · Nov 4, 2014

-Logzor said:
I had no idea it would take that much limewater to equal the two-part. So the 140 mL that I'm adding has almost no impact?

Are you saying that the 230 mL I'm dosing of two-part is equal to 10,000 mL of limewater? Is this doubled to include the calcium that I'm dosing as well? I'm not sure if you mean the limewater is 45 times less potent than the combined or individual two-part.

What kind of change in pH are we talking if I made this transition. Theoretically I could do it but I would need to move from 5 gallon dosing buckets up to 10 gallon dosing buckets!

People usually replace most or all of the evaporated water, which is often 1-3% of the tank volume daily.

Adding 1.25% of the actual water volume with saturated limewater each day adds about 1.4 dKH of alkalinity and about 10 ppm of calcium.

Yes, 230 mL of my DIY two part equals about 10 L or limewater.

-Logzor · Nov 4, 2014

zemuss said:
Logzor,

Have you considered replacing the dosing of the two part with a Calcium reactor and supplementing with the lime water dosing? Might be cheaper.. WIth a system this big two part might start to get expensive.

Randy Holmes-Farley said:
The limewater is roughly 45 times less potent than the two part.

So to stop 20 mL of each part of the two part needs roughly 900 mL of limewater.

That said, there is never a 1:1 swap when changing additives that also change pH, since the pH change itself alters demand in the tank.

zemuss said:
Is the Limewater part of your ATO system? Maybe this is where having limewater inline with an ato is better than as a dose parameter?

This is definitely something I'm looking at implementing, my concern was variation in evaporation rates throughout the year. I like the dosing pumps because I have complete control.

What would be the estimated change in dkh / calcium per day if I replaced my RO/DI with saturated limewater?