Best way to raise Alkalinity?

[bamf25]

I have been having som eissues keeping my alk up recently. I have a 120g DT with sump, and small fuge (15g) with cheato. it is a young tank and most of the corals are small, but I do have a fair sized favia, acan, frogspawn, hammer, a few small chalices, a few acan frags, a good sized plate monit, a new birdsnest frag, along with a couple zoa colonies and mushroom colonies, and a good sized toadstool My Mg holds very steady around 1350, and my calc sticks around 440, with just a normal 15% or so water change every 7 to 10 days. My alk on the other hand has been dropping about 1 to 1.5 dkh per week. I already know the chemistry where calc drops much slower in relation to the alk. I am dosing kalkwater in my ato at it is near saturated. Other tank numbers, ph 8.05, phos 0.08, ammonia 0, nitrite 0, nitrate trace amount, temp 78, salinity 1.025. I have had some algea issues recently, but I started running gfo fairly heavy the last few weeks and growth has slowed significantly. I have been hand dosing alk to keep it up.

What is the best way to suppliment my alk?

[Randy Holmes-Farley]

The best one time correction would be baking soda.

For long term use, I'd make or buy a two part additive for calcium and alkalinity, but if the additional needs are small then a bit of baking soda dosed however often you need it (in addition to the limewater) is a fine plan. :)

[bamf25]

I have been using the alkalinity from 2 part solution to raise my alk thus far, I just wish the klakwater would keep it up there better.

[sig_1959]

`I have the exactly the same problem with my 120g :hmm1: and looks like our tanks consume it fast.

I do not know if you follow instruction to mix Kalk, but guys on the other forum mix 2 table spoons/g ( instead of 2 tea spoons)and drip 5G per week

[Randy Holmes-Farley]

I have been using the alkalinity from 2 part solution to raise my alk thus far, I just wish the klakwater would keep it up there better.

OK, that's a fine plan, but if you have the two part, I'd use both parts unless calcium is already higher than you want. Small additions to alk with both parts will not noticeably boost calcium, but over time calcium will decline if you neglect that part, then you'll need a bigger boost.

[autodave]

What about using a salt mix like Red Sea Coral Pro with a high dkh?(Thats my plan at least :) )

[bertoni]

Many tanks have such a high rate of alkalinity consumption that water changes won't help. My tanks dropped about 2-3 dKH per day, for example.

[TprMoore]

I've had a lot of good results dosing with SeaChem's Eight.Four. and Calcification. dKH is 9, and calcium is 420ppm....

[autodave]

Many tanks have such a high rate of alkalinity consumption that water changes won't help. My tanks dropped about 2-3 dKH per day, for example.

Can I ask how you maintain your Alk?

[lgray13]

I use Mrs Wages pickling lime and add it in my auto top off. Keeps the alk and ph stable. My calcium so far has stayed stable at 460-480 but I am starting to research calcium reactors as my corals are growing well.

[bertoni]

Those tanks consumed a lot of 2-part and some kalk, too.

[loftism]

I have same issue. Loosing alk to fast i think i know why... GFO pulls carbonate hardness from the water. Want proof go to Marine Depot's website and look up Phosban it mentions it will lower alkalinity. I use two cups of BRS GFO per month and have to dose baking soda for a week to to bring it up. Seems to happen mostly when the GFO is new. I admit i this is a bit of new angle to GFO and i dont have months upon months of proof but it seems to fit. Please anyone else noticed this issue with GFO? BTW i have no plan on stop using GFO my tank is pretty new and i have calicium reactor not setup yet, im hoping this will be a non-issue after.

[Nyc Joe]

I've been looking into adding some Kalk to my top off.
Every week supposedly keeps it in check.

[Randy Holmes-Farley]

I have same issue. Loosing alk to fast i think i know why... GFO pulls carbonate hardness from the water. Want proof go to Marine Depot's website and look up Phosban it mentions it will lower alkalinity. I use two cups of BRS GFO per month and have to dose baking soda for a week to to bring it up. Seems to happen mostly when the GFO is new. I admit i this is a bit of new angle to GFO and i dont have months upon months of proof but it seems to fit. Please anyone else noticed this issue with GFO? BTW i have no plan on stop using GFO my tank is pretty new and i have calicium reactor not setup yet, im hoping this will be a non-issue after.

GFO can bind a little carbonate directly, but that effect is fairly small and happens very fast. The main reason that alkalinity drops more and more over time in the tank is due to localized precipitation of calcium carbonate. That is easily seen as a deposit that forms on and downstream of GFO, probably because free iron catalyzes the formation of calcium carbonate from supersaturated solutions like seawater.

So since that is the case, you are not primarily looking at unbalanced demand for alkalinity, but added demand for both calcium and alkalinity. Consequently, increased addition of both from your reactor, or from any other method (like limewater or a two part) will be able to deal with this issue just fine.

FWIW, when you are not meeting demand for both calcium and alkalinity, you notice the effect first in alkalinity. You'd see a drop of about 18 ppm calcium for each 2.8 dKH drop in alkalinity (20 ppm calcium if no magnesium gets into the structure). Since folks can easily detect a 1 dKH drop in alkalinity, but really couldn't reliably detect a 6 ppm drop in calcium with our test kits, they assume they have unbalanced demand, when in reality that most often is not the case. :)