How high can you go on dKH before negative impact?

[JoelA7]

Hi,

Tests today

Ca=450
dKH=15 (!!!!!)
Mg=1450
pH=8.0 via probe and 8.3 per salifert (salifert is always .2 higher even when probe is freshly calibrated)

All other values pretty spot on. Tank looks healthy with slight bleaching. It's still young and I'm still getting the hang of it.

So my question is whether there would be harm to my livestock from the elevated dKH? (I know that there may be a little more precipitate etc.)

Thank you.

[apexkeeper]

I've had my dKH up to 16 before (accidental overdose) with absolutely no ill effects. Just let it fall back down naturally.

[BrentH]

Do u have any corals in the tank

[JoelA7]

Yes. Varying degrees of health. Slight bleaching of a Favites as of yesterday. Today a Duncan which has been excellent overnight changed to fully retracted. 1 Acan very good another fair. A trachy colored up as good as its been since I got it but expansion slightly reduced. Ricordia normal nice. Green striped shrooms not fully expanded. Yellow polyps good. Zoas and palies good. Green star and silver Xenia good. Short stem blue polyps good. Added a 65g reefcleaners snail pack yesterday and 12% water change just now.

[bertoni]

Since the corals are having some trouble, I might try another 10% water change each day for a bit longer, but most often, such overdoses cause only a little damage, if any at all.

[tmz]

Changes in alkalinity, especially out of the recommended range ,7 to 11 dkh, can give some corals trouble.

[JoelA7]

I've turned off the Ca reactor. Will let it diminish to 10 and add some CaCl to keep Ca high. Then start it up again.

[JoelA7]

Update. 5 days or a bit more w Ca reactor off and here are values.

Ca. 410
dKH. 9.5
Mg. 1500

PO4 on new Hanna 713 was 1.07 ppm but that's operator error. I am sure I zeroed it out wrong so will review instructions when I'm awake again.

So the Duncan is open again. Expanded a bit more each day for 3 days. Still not great but better. Zoas brighter. Mushrooms expansion is better too. Favites expansion at night good. Color still faded. Yellow polyps noticeably happier. More cyano in one corner but quite limited. New CUC additions working on algae.

I'm stunned how fast Ca and dKH came down. Damn this is technical and artistic all at the same time. ...

[wcarterh]

JoelA7, did you dose any Mag during those 5 days?

[JoelA7]

Did not dose Mg. Test kit variance I assume.

[tmz]

Those new numbers look good to me. I'd concentrate on keeping the the steady and calcium over 400ppm . Magnesium at 1500ppm is ok and shouldn't drop below 1300 for a long time if at all with water cahnges.

[JoelA7]

I've started the Ca reactor up again but with 6.9 and 7.0 as the pH range. I'll see if that will maintain these levels. I might push the Ca a bit higher with CaCl once I get the CO4/HCO4 stable.

Plus!!! I just looked over the salt mix sticky. I have 200g of Reef Crystals to go. It mixes to dKH of 13. I think I will consider changing salt mix in the future. But I am changing about 10-12% each time so that isn't too large a bump.

[tmz]

I use Coralife which gives me around 9.5 at 1.026 which is where my sytem sits. Smalll cahnges minimize the impact of alk variances in salt mixes and other variations. FWIW I do 1% per day.