Whats the maximum?

Cory · Nov 12, 2015

Im thinking id like to max out alkalinity and calcium so i can let it fall and raise it again every week instead of every two days.

Could i have 500ppm calcium and 12dkh alk without problems? Then let it drop or try and keep it there.

Randy Holmes-Farley · Nov 12, 2015

Calcium is fine. Alk is more of a concern, but 12 dKH may be OK. The concern with high alk is more abiotic precipitation of CaCO3 (and possibly burnt tips on SPS in a ULNS system).

The swing over a week may not be preferred by many corals, however.

Cory · Nov 13, 2015

What about potassiums max? Could i avoid burnt tips with say 11dkh? Would i have too high ph at 11dkh?

Currently my parameters are:
Potassium 420ppm
Calcium. 420ppm
Alkalinity. 8dkh
Magnesium 1200ppm
35ppt salinity

I was low on all a few days ago. 1130mag, 7dkh alk, 360 cal, 360 potassium. I raised them all at once - no apparent issues with any livestock. Just concerned about the epsom salt sulphate skewing upward, i dont have chloride version.

redfishbluefish · Nov 13, 2015

It is my belief that the more stable you keep ALL parameters on your tank, the happier the inhabitants will be.

I use to manually dose once a day, and even though it is anecdotal, when I went to dosing multiple times over the day, I saw improvements in appearance of my corals.

Those swings, especially in alkalinity, will be problematic. You're corals will not be happy.

Cory · Nov 14, 2015

Ill try with the stability thing. I understand the risks and all that.

while i like the idea of stability, i dont like testing daily or every few days.

While i like the idea of a calcium carbonate reactor, i dont like the idea of a consistabt dose without testing. What if it gets too high.

Same with limewater, wont it get too high or low based on evaporation?

redfishbluefish · Nov 14, 2015

As a new reefer or new doser, you test every day, or maybe even multiple times a day. As you age with you tank and you know its personality and needs, you will find yourself doing less testing. I have dosing pumps and I'll guess I test once a month. Most times everything is spot on. On occasion I'll have to slightly adjust one of the pumps up or down.

Bottom line.....it will get easier.

Cory · Nov 14, 2015

I guess ill just buy the hanna checker for alkalinity.

Randy Holmes-Farley · Nov 14, 2015

Cory said:
Same with limewater, wont it get too high or low based on evaporation?

There is negative feedback on alkalinity rising or falling because the demand rises and falls with it. So if you are adding more limewater and alk (and pH rise), demand rises, causing it to drop back.

It is not perfect, but it makes the exact amount of evaporation not all that critical, IME.

Cory · Nov 14, 2015

So your saying higher ph will help the corals grow faster and that the extra alkalinity and calcium wont do much harm because calification happens faster at higher ph which limewater does?

Randy Holmes-Farley · Nov 14, 2015

Cory said:
So your saying higher ph will help the corals grow faster and that the extra alkalinity and calcium wont do much harm because calification happens faster at higher ph which limewater does?

Higher pH and higher alk drive more abiotic precipitation and more hard coral growth. Both of those processes serve to drop alk back down. So I'm just saying it is a bit of a self limmiting issue, and not than many folks get spikes of excessive alkalinity (say, over 11 dKH) from limewater alone.

Cory · Nov 14, 2015

Awesome ill start using limewater!

You got an article about limewater? Thanks a lot.

Randy Holmes-Farley · Nov 14, 2015

The first is the most general:

What Your Grandmother Never Told You About Lime by Randy Holmes-Farley - Reefkeeping.com

Chemistry And The Aquarium: Metals In Limewater ? Advanced Aquarist | Aquarist Magazine and Blog

The Degradation of Limewater in Air - Reefkeeping.com

Aquarium Chemistry: Magnesium And Strontium In Limewater ? Advanced Aquarist | Aquarist Magazine and Blog

Pete polyp · Nov 14, 2015

In my experience the demand for calcium and alkalinity exceeds normal saturation of limewater. I don't have very many corals in my tank at the moment and I'm dripping kalk slurry (4tsp/gallon) and I'm still having to dose calcium and alkalinity. The kalk does add some and reduces the need for dosing, but does not eliminate it completely. You may get away with not having to dose, but with a large amount of hard corals that's unlikely. At one point my tank was consuming 4dkh daily, so normal saturation limewater was nowhere near enough.

Randy Holmes-Farley · Nov 14, 2015

Pete polyp said:
In my experience the demand for calcium and alkalinity exceeds normal saturation of limewater. I don't have very many corals in my tank at the moment and I'm dripping kalk slurry (4tsp/gallon) and I'm still having to dose calcium and alkalinity. The kalk does add some and reduces the need for dosing, but does not eliminate it completely. You may get away with not having to dose, but with a large amount of hard corals that's unlikely. At one point my tank was consuming 4dkh daily, so normal saturation limewater was nowhere near enough.

That's certainly true that it can't always meet the demand for a hard coral tank, especially an SPS heavy tank. If you top off 2% of the volume daily, that's about 2.3 dKH.

But it has always met all needs for my mixed tank, even with some SPS and several large LPS corals that grew well for many years.