pH mainly drops at night. I've been trying to use my Kalk reactor to offset this drop. My Kalk reactor runs only at night, but so far it has not made any noticeable change in the pH drop. I continue to increase the nightly amount.

Using kalk only will maintain add calcium and help with alk. levels but I have always found the alkalinity to drop in kalk only tanks. I and others doing the same, add a buffer once a week or so, to maintain alk.

My co2 reactor, maintained both my calcium and alk. as Brad mentioned his did. I found my alk was always on the higher side, pushing around 11.2dkh.

I think most running a co2 reactor, use a kalk reactor or drip, to help boost calcium in a heavy demand tank and also as mentioned, to help with ph levels. However I know of several co2 reactor users who dont follow this idea, as there reactors are sized large enough to provide calcium & alk, plus they also seem to maintain high enough ph levels with no kalk.

I like kalk myself, as its cheap and easy to use. I have never used a reactor though, just dripping now or mixing it in my top off tub when running my larger tanks.

I would say keep the co2 reactor running the same or back it down a bit and keep using a good kalk mix to bring calcium levels up, with perhaps a bit of Reef Advantage or whatever you use, to increase the calcium levle some.

Whats the alk. reading on the reactors output? If mine got a bit ot high, I think I decreased the co2 amount a little, which usually lower it. Cant remember for sure but think mine was running in the low to mid 20,s dkh area.

Hi Brad, thanks, that is basically what I'm trying as I try to dial in the two reactors together. (Ie. using the two-parts until I get Ca=390 and Alk=3.0, then let the reactors try to maintain after that point.) It's just that over time, Ca will will fall, and Alk will rise. Which wasn't quite was I was expecting, I was expecting both values to rise (or drop) together. If I run the kalk by itself both values will drop. If I run the Ca by itself I should theoretically be able to retune to the system's draw rates but I was hoping to add kalk to the mix because it helps to precipitate out phosphate (or so I thought).

I dunno maybe I'll just give up on the kalk for now. It's not like I have any SPS left, so the draw should be fairly low anyhow, but I was hoping to maintain the levels for the benefit of the other things I have left (clams and LPS).

Thanks Doug. I'll test the reactor's Alk output, I have no idea what it's at, I've only measured pH of the effluent.

One thing catches my eye in what you just said - "good kalk mix." I'm wondering if part of my problem is I'm using Mrs Wages pickling lime (Someone gave me theirs when they left the hobby). I don't really like the stuff very much. It turns poo brown after a week although the pH is still 11ish so I think it's still working but nevertheless I'm wondering I should switch to a proper kalk mix.. I only use a few tablespoons per week or two so it takes me forever to use it up..

Of course, it could be something related to the Ca/Alk that your specific tank uses. It think it is fairly accurate to say that both Kalk and Ca reactors deliver both Ca/Alk in a mostly balanced way.

Holmes-Farley also says that often having one of these parameters a bit low is an indication of not enough of the balanced Kalk or Reactor...as opposed to concluding that you need to chase Ca or Alk separately.

That's just the thing, you can't chase Ca and Alk independently when you have a reactor. I am starting to appreciate the Balling method instead :lol: Or just adding the stuff manually, it's just that I can't stand wondering at 10pm at night "Did I remember to add my Ca additive before I left for work this morning? How come I can't remember?" ... That's the beauty of the reactors - once dialed in they are set-and-forget but ... OTOH dialing them in can be such a pain. I can dial in a single reactor perfectly but now adding a kalk reactor to the mix, it just seems I can't wrap my head around what's going on in there. :redface:

I never used the pickling lime much Tony, so cant comment on it. Seems like a lot of aquarists in the US are though. I use Ben,s kalk. Good grade and a decent price. I believe Quinn also sells it at Prairie Reef Supplies. Before that I always used ESV.

If you wish to discontinue the kalk and are happy with ph levels and the co2 reactor, then just use a calcium additive to bring the level up. It should not effect the alk. The co2 reactor then can be set to keep both at par.

I also use the kalk to precipitate the phosphate but have no idea if its doing that. :lol:

I run both, kalk and ca reactors, although my kalk pulls water from my top-off bucket, before heading into the tank.

My system seems to have settled on 9-10dKH, and 420-460 Ca.

I have some of Ben's kalk too (another hand-me-down from someone departing the hobby). I figure I would use up the pickling lime first just because I want to get rid of what I've got first before moving onto new stuff. But at only a few tablespoons into the kalk reactor every 2 weeks it's just taking forever to use it all up. I have a similar problem with PE Mysis, through participation in group orders and some hand-me-downs I found myself sitting on about 30 packages, I've used up a lot, but still have about 20. At my current rate of consumption (I feed mysis to 3 tanks every day so it's not like I'm overly stingy - but it's about a .75" square of mysis split into 3 tanks so it's not like I'm dumping the stuff either), it takes me about 2-3 months per package to use it up. 2-3 months times 20 packages = 40 to 60 month supply :eek: I'm thinking I'm going to have to start trading some of this stuff away, it just won't hold that long.. :lol:

Catherine those are rather ideal looking numbers. Man I wish I knew what I could adjust to make mine similar... :neutral: I wonder if it's a case of too much calcium reactor / not enough kalk? I have the drip rate set on the kalk reactor so that it doesn't exceed evaporation. If I set the pump to 10% or higher of its rated capacity it will overtake evaporation (luckily it's a very slow trend and easy to spot after a day or so, so it's not like I'm in danger of overflowing the sump unless I get VERY inobservant..).

At my old place when I ran both I had the kalk run directly into my float valve. I switched to a metering pump so that I wouldn't have to worry about the valve clogging anymore.

Ok here's my next question, for those with kalk reactors, how often and for how long are you running your mixing pump?