Alkalinity advice

Tori · Mar 14, 2016

My alk has been trending downwards and I think it has finally hit the danger zone. I have a 20 gallon mixed reef that has been running for about 6 months with a few lps coral, a couple of birdsnest and some zoas spread around the tank. I have also been growing a lot of coraline so maybe all this has been depleting my alk. I also have four small fish if that matters. I tested a couple of days after my last 10% water change and my alk had already dropped to 5 dkh. It use to stay at around 7 for the most part. Anyway my question is, is it time to start dosing? I would prefer something I could mix in with my auto top off water since I don't have a doser set up. I've read that kalkwassre will help maintain alkalinity but not sure if it will help in my case with it so low already. Would anything else be good to start mixing with my rodi water for top offs? Any advice would be appreciated! My other parameters are:

Nitrate ~10
Nitrite 0
Pho4 .025
Calcium 440
Magnesium 1280
SG 1.024
and Alkalinity 5 dkh

Thanks!

Salty0331 · Mar 14, 2016

I would suggest a good quality 2 part additive like B-ionic. Personally I use seachem's premium line 3 part, Aqua Vitro. I use this so I can fine tune the base elements, Alk, Ca, and Mg.

Salty0331 · Mar 14, 2016

Kalk is a good way to maintain Alk and Ca and most use in their top off water to maintain those levels.

Tori · Mar 14, 2016

Salty0331 said:
I would suggest a good quality 2 part additive like B-ionic. Personally I use seachem's premium line 3 part, Aqua Vitro. I use this so I can fine tune the base elements, Alk, Ca, and Mg.

That sounds good. Can you mix it in with your top off water?

Salty0331 · Mar 14, 2016

I personally do not....i add to sump....i would forst test the Alk of your top off water....if its low i would a bit to equal the tank alk to avoid a pull down when you add top off water

Randy Holmes-Farley · Mar 14, 2016

You can use limewater (kalkwasser) in your top off. I do.

You could also put the alk part of a two part (DIY, like from BRS, or a commercial one like B-ionic) into the top off, and then manually add the right amount of calcium to balance it once in a while whole the demand is low, and more often as it increases.

Tori · Mar 14, 2016

I'll probably order some kalkwassre tonight. I stopped by my lfs on the way home and grabbed some sachem reefbuilder carbonate before I read this, not sure if I'll use it or not. I'm still unsure if kalkwassre will raise my alk or just keep it from dropping more. Sorry for being dense

, I'm going to blame the time change and lack of sleep.

Lenny_S · Mar 14, 2016

Kalk is good for maintaining Alk and Ca, but not great for making adjustments as it will raise your pH a lot if you add a decent amount. You can use baking soda to raise your Alk without much impact to pH. I would do like .5 DKH like every other day until you at about 8 or so. From that point Kalk is a great option to maintain Alk and Ca.

Tori · Mar 14, 2016

It's starting to make sense. I've read through Dr. Holme-Farleys articles a few times now but I still can't say I understand it all completely. Looks like I need to add .1 tsps of either the sachem reef builder or baking soda every other day to add .5 alkalinity every other day. That seems like a good pace. Thanks so much for the advice everyone!

Randy Holmes-Farley · Mar 15, 2016

Tori said:
I'll probably order some kalkwassre tonight. I stopped by my lfs on the way home and grabbed some sachem reefbuilder carbonate before I read this, not sure if I'll use it or not. I'm still unsure if kalkwassre will raise my alk or just keep it from dropping more. Sorry for being dense , I'm going to blame the time change and lack of sleep.

If you add more than the daily demand in your tank, it will raise it. Adding 1.25% of the water volume in saturated limewater will add 1 meq/L (2.8 dKH) of alkalinity and 20 ppm of calcium.

Lenny_S · Mar 15, 2016

Randy Holmes-Farley said:
If you add more than the daily demand in your tank, it will raise it. Adding 1.25% of the water volume in saturated limewater will add 1 meq/L (2.8 dKH) of alkalinity and 20 ppm of calcium.

Since the calcium is already reading 440 ppm wouldn't a slow alkalinity adjustment with baking soda be a better option in this case?

Tori · Mar 15, 2016

Randy Holmes-Farley said:
If you add more than the daily demand in your tank, it will raise it. Adding 1.25% of the water volume in saturated limewater will add 1 meq/L (2.8 dKH) of alkalinity and 20 ppm of calcium.

Ah, I see. Thanks! It's getting more and more clear now. I just realized I forgot to list my pH. It normally ranges from 7.89 to 8.14 but it's been dropping down to 7.78 and only going up to about 8.06 lately. I monitor using my controller which has the lab grade pH probe attachment. Not sure if that changes anything but I meant to post it originally anyway. I just figured the low alk was the more important issue to address.

ycnibrc · Mar 15, 2016

Hi randy I'm trying to lower my alkalinity but even when I shut off the cal reactor alk still not dropping. I wonder if dosing vinegar will keep the alk from going down.

Randy Holmes-Farley · Mar 15, 2016

Lenny_S said:
Since the calcium is already reading 440 ppm wouldn't a slow alkalinity adjustment with baking soda be a better option in this case?

Depends on your target for calcium. I do not think it matters either way. 460 ppm is certainly fine, and so is 440 ppm.

Randy Holmes-Farley · Mar 15, 2016

ycnibrc said:
Hi randy I'm trying to lower my alkalinity but even when I shut off the cal reactor alk still not dropping. I wonder if dosing vinegar will keep the alk from going down.

Vinegar dosing should not alter the trend in alk dropping over time (or not).