Kalk Dosing

[mgraf]

My pH probe is in my over flow across the 4 ' tank. Maybe the kalk ran across the surface current into the overflow, I don't know. I put the probe in the over flow because it is more isolated there, I have several wires that enter the same hole in the stand and I wanted to make sure there was no electrical interference. Prope was calibrated at beginning of the week and read dead on with 10.0 calibration solution again last night. pH did reach a high of 9 one evening but, that was when I decided to move the probe away from other electrical devices. Haven't checked DKH tonight but pH is 8.36. Which means the reactor is being bypassed and plain RO water is being used to supplement evaporation. When I got home from work earlier this evening, the pH was 8.23.

 

[mgraf]

I run an ATS which is on a reverse light cycle from my Dt, there is never a complete lights out in the system, either DT is in light cycle, or sump is lit. The ATS is lit 18 hours a day. I evaporate approximately 1 1/4 gallons a day with ATS running. My pH before the reactor would never get above 8.0 before the reactor.

 

[jrok3401]

To the OP: I've never really felt like keeping pH at a certain level was really necessary. As long as your KH is at an acceptable range, you should be OK. Randy's pH article states an acceptable pH range in a reef tank is 7.8-8.5 with calcium levels at 400 or greater.

http://reefkeeping.com/issues/2007-05/rhf/#3

In other words, if you keep your alkalinity and calcium in range, and you don't have some other issue driving your pH lower or higher than Randy's recommended range, then why bother chasing pH numbers?

Is you tank outside the 7.8-8.5 range to start with? You did not post where your pH is at and what tank pH you wish to achieve. No sense in seeing a problem if there is not one to start with.

Well currently I am in build phase. Took a small break for about a year. But someone I bought some corals from controlled her ph with Kalk but it was done through a controller not through topoff. As a result or so she claimed her corals grew like they were on steroids. Lol. So that's where I got the idea and why I wanted to ask to see if anyone else has done this. I personally will just use my old Kalk reactor and run it through my topoff.

 

[Syntax1325]

I find it easier to add a 1/4 cup kalk to the reactor and maintain it and keep it clean as apposed to keeping the reservoir clean and exposing pump to residual kalk and byproduct.

OK, that's fine. I don't clean my reservoir, FWIW.

pH 8.5 is fine, but if you want it lower, more aeration of the water or less kalkwasser as you plan seem to be fine options. If you pH control this way, frequent calibration of the probe would be in order.

If I may please interject a question here? Randy, if you don't clean out your kalk reservoir are't you changing its concentration each time you add to the container?

I have recently started kalk in a five gallon bucket that sits near my tank. I have been premixing 1/2 tsp (the first dose of kalk was 1 tsp, then reduced it) in a gallon jug and then dumping it in my topoff bucket about every two days (I am using a jbj ato) I don't bother to let it settle because the concentration is so low; however, I have noticed that it still precipitates in the topoff bucket. Essentially, each batch of kalk I'm adding to my bucket mixes all the previous batches' precipitate. Question: is this bad? Will it lead to inconsistent results? Can you recommend a better procedure if necessary?

I think that 1/2 tsp of kalk keeps my calcium at 450 and alk at 8.3, not sure if that is because of the added precipitate from multiple batches added to my reservoir... I cleaned it out last night, we'll see what happens.

Sorry for interrupting the thread again, I hope this question helps others as well.

 

[Randy Holmes-Farley]

The solids are necessarily bad, but will over time accumulate more and more impurities that don't dissolve. I wouldn't prefer to add the accumulated debris from a years worth of settling.

Most of what is there in mine is calcium carbonate, which just sits there, or if I stir, suspends then resettles. I'm mixing up 3 connected 44 gallon Brute cans at a time.

Even if there is substantial extra calcium hydroxide present, it won't dissolve to higher than saturation.

In reality, what I do is stir it and add calcium hydroxide as necessary to reach a conductivity of at least 7-8 mS/cm (maybe 70% or more of saturation, which is about 10.3 mS/cm).

 

[Syntax1325]

Thanks Randy. So, I should have no concern about an increase in potency of the kalk solution since my mix is less than saturation? In other words, the precipitate will not dissolve when I add more mixed water to my topoff container since I'm well below the saturation point for the kalk.

I'll start prefixing the solution in a separate container and let it sit for 24 hours before dumping the clear liquid into my tipoff to avoid having to clean the topoff of precipitate.

 

[Randy Holmes-Farley]

If you add less than saturation and mix well, the solids that remain won't be able to redissolve appreciably the next time. They have been converted into calcium carbonate and other insolubles.