Dosing Kalk in Auto Water Changes

[Atilla_87]

Hey all,
I'm new to the forum, but have been reefkeeping for awhile. I'm struggling with an issue. I'm upgrading to a new 225 reef tank with a 75 gallon sump/refugium. I plan to set up a 100 gallon reservoir of premixed saltwater. I will do continual water changes by programming peristaltic pumps to discard about 3.5 gallons per day from the aquarium, while matching that amount from the premixed tank into the aquarium. In this way I will change about 100 gallons of water (or 33%) per month. The RO will be plumbed directly into a float in the sump to offset evaporation.

I would like to dose kalkwasser through my water change system. I was thinking I could dissolve the kalk into the 100 gallon tank when I am mixing a new batch of saltwater. The problem I am having is to determine the amount of kalk to mix. I know most people mix 2 tsp per gallon when adding to their auto top off. However, I'm worried that I will be adding more to the aquarium using my water change system than one normally would with an auto top off that is only adding to replace evaporation.

Any help on this issue would be appreciated. Anyone have experience with this type of system?

 

[SAZ03]

I am wondering the same exact thing. Subscribing to this thread!

I THINK the answer I have found is that we add 1TBS per gallon but I will wait to see what the experts say. I like the idea of auto water changes too, nice idea.

 

[disc1]

You can't dissolve kalk into seawater, it would precipitate. You can only mix kalk into freshwater so most people do it though the ATO.

 

[Atilla_87]

You can't dissolve kalk into seawater, it would precipitate. You can only mix kalk into freshwater so most people do it though the ATO.

Dang, did you have to go rain on my parade like that?

 

[Atilla_87]

You can't dissolve kalk into seawater, it would precipitate. You can only mix kalk into freshwater so most people do it though the ATO.

What about mixing the kalk with the ro water first, then mixing in the salt?

 

[Jpugh73]

Nope still not going to work, you are going to need a separate setup for the ato

 

[disc1]

What about mixing the kalk with the ro water first, then mixing in the salt?

Doesn't matter which you add first, they won't stay in solution together. As soon as the salt hits the kalk you'll have a snowstorm.

 

[dirtycontour]

Would a two-part work?

 

[disc1]

Nope. Same problem.

Calcium carbonate is already super staurated in seawater. You cannot add excess of either alkalinity or calcium without knocking both out of solution.

 

[disc1]

I mean you could use a two part to bump up the levels in your change water it they are low, but you can't add enough to use it as a way to dose the tank up.

 

[Aquarist007]

I mean you could use a two part to bump up the levels in your change water it they are low, but you can't add enough to use it as a way to dose the tank up.

IMO no matter what the amt as soon as you mix them together they precipitate.

 

[Atilla_87]

I already have two part with dosing pumps set up for direct feed into the sump. I've been fighting low PH though, so I'd like to add kalk, and supplement if needed with a 2 part. Sounds like I'll have to rethink my kalk situation though.

 

[Aquarist007]

I already have two part with dosing pumps set up for direct feed into the sump. I've been fighting low PH though, so I'd like to add kalk, and supplement if needed with a 2 part. Sounds like I'll have to rethink my kalk situation though.

if your adding alk and your alk is within acceptable ranges IMO your low pH is a carbon dioxide problem. This can be addressed by cranking up your skimmer, removing any covers from the top of the tank, directing a power head to surge the surface water and opening a window in the fish room.

 

[disc1]

Sounds like I'll have to rethink my kalk situation though.

Your ATO is your best friend in this situation.

 

[Siebo]

Dosing Kalk in Auto Water Changes

You need to crunch some numbers here. Determine what numbers you are tying to add in addition to your dosing. saturating or super saturating your ATO may be enough. You need to know rate of evaporation to determine the amount of Kalk going it. You could always decrease the water change volume to increase top off needed.

I assume you know current alk and cal demand since you are dosing. You would need to most likely decrease your dosing if you do this.

This will help with calculations
http://reef.diesyst.com/chemcalc/chemcalc.html

 

[dirtycontour]

I've been fighting low PH though

Have you thought about a CO2 scrubber?
http://www.reefcentral.com/forums/showthread.php?t=1889552&highlight=co2+scrubber

I've been using one for about a year. It has raised my pH by about .2. I don't really notice a difference in the tank, but it does keep my pH higher...

 

[Bryopsis]

Have you thought about a CO2 scrubber?
http://www.reefcentral.com/forums/showthread.php?t=1889552&highlight=co2+scrubber

I've been using one for about a year. It has raised my pH by about .2. I don't really notice a difference in the tank, but it does keep my pH higher...

I got a 50 lb bucket of soda lime, I think it'll prolly last a good 2 more years... lol (very helpful for constant ph)

 

[Aquarist007]

Reading through the thread again I don't see what level your pH is?