Time to start dosing?

[00Dan]

I’ve been testing particularly particularly low alkalinity recently on my Nuvo 40 (~28 gal water volume). I usually do a 30-35% water change once a week; I use reef crystals.

For reference, my last change was this past Monday. I tested today and my parameters were as follows:
salinity 34 PPT
alk 5.9 dKh (Hanna)
Ca 476 PPM (Hanna)
Nitrate 10 PPM (API)
Phosphate undetectable (API)

Is it time to start dosing Alk, or perhaps just changing my water change schedule slightly? Could something else be out of whack causing alk but not Ca to be consumed?

 

[qasimja]

do you check your mag?

 

[00Dan]

do you check your mag?

I did not. I have a kit but no reagents.

 

[bhodges82]

Please post a picture to show how much coral you have.

 

[gainesvillereef]

How old is the tank? Are you using any additives?

 

[jcook54]

Corals use calcium and Alk in a ratio in order to build their skeletons and I'd feel a lot cooler right now if I could tell you what it was. In my experience a new system and some older one's (like mine) use more Alk than calcium. It seems to be taken up quicker that the calcium but I'm not even sure the tests allow for an apples-to-apples comparison. Regardless, Reef Crystals is known for having higher alk levels and at 5.6dKh, I would dose some alkalinity.

 

[00Dan]

Attached is a current shot to give an idea of the amount of coral. The tank is about 9 months old.

For just a low alk issue, what would be the best way to bring that up (kalk, just alk part of 2 part, all in one?)

 

[bhodges82]

Attached is a current shot to give an idea of the amount of coral. The tank is about 9 months old.

For just a low alk issue, what would be the best way to bring that up (kalk, just alk part of 2 part, all in one?)

View attachment 32279

It seems like that isn't an excessive amount of coral, definitely not enough to drive your alk down to the levels they are at. If it were me, I would use 2 part solution to correct the alk level and test for confirmation then retest after a week to see how much your tank consumes. If you are losing more than 1 dkh over the course of a week it may be a good idea to start dosing. Your coral should respond well to better parameters, this is going to mean more growth which means more dosing so keep up with the testing.

Try to only raise alk level by 1 dkh per day so that you don't shock your coral.

Have you tested with any other test kit to confirm your test results?

 

[00Dan]

Have you tested with any other test kit to confirm your test results?

API tested to 6 dKH.

Interestingly enough, I tested a fresh batch of 35 PPT water with the hanna checker and it only tested to 8.8 dKh. I know Reef Crystals are supposed to mix higher than that, perhaps something is causing it to precipitate out?

 

[00Dan]

BRS 2 part and Mg reagents are on the way.

From what I understand about dosing I should aim for approximately 1 dKh increase per day, and dose Ca and Mg as needed to keep them in line. What value of alk is generally recommended? I know there is some personal preference but from what I’ve seen it ranges anywhere from 7 to 10 dKh.

Anything I’m missing?

 

[bhodges82]

8 is a good baseline, it allows for a little error in either direction.

 

[ichthyoid]

I thought fresh mixed Reef Crystals typically measures like ~12dKh?

Why I ask-
If that’s true, the API test is off by ~30+%

 

[00Dan]

I thought fresh mixed Reef Crystals typically measures like ~12dKh?

Why I ask-
If that’s true, the API test is off by ~30+%

A quick trip to Google tells me that it’s supposed to mix that high but it’s not unheard of for it to be inconsistent and mix lower. Both my Hanna checker and the API test were reading similar here. I have a Seachem test I can dig up but I doubt it will be substantially different.

 

[jcook54]

I've gone round-and-round with Reef Crystals about their Alk levels. I've tested freshly mixed batches a lot over the years and I've never ever seen anything over 9.0 and very often find it closer to the 7.0 range. The last time I talked to their customer service was when I had a batch that tested at 5.4 dKh.* They gave me coupons for free salt and I still use the stuff but I've never seen the Alk very high at all. I used to worry about precipitation or something like that going on but settled on the Alk levels just being on the low side.

*Reef Crystals mixed to 1.025 and tested with Salifert & Hannah checker.

 

[00Dan]

I've gone round-and-round with Reef Crystals about their Alk levels. I've tested freshly mixed batches a lot over the years and I've never ever seen anything over 9.0 and very often find it closer to the 7.0 range. The last time I talked to their customer service was when I had a batch that tested at 5.4 dKh.* They gave me coupons for free salt and I still use the stuff but I've never seen the Alk very high at all. I used to worry about precipitation or something like that going on but settled on the Alk levels just being on the low side.

*Reef Crystals mixed to 1.025 and tested with Salifert & Hannah checker.

It almost makes me wonder if they’re just relabeling Instant Ocean and charging more...

 

[00Dan]

I tested again today after a 10% water change

Salinity 35 PPT
Mg 1390 PPM
Ca 457 PPM
Alk 5.9 dKh

I have the BRS two-part solutions mixing now. I'm a bit surprised my magnesium levels are testing normal. It seems for now just dosing alkalinity is my course of action; hopefully bringing it up won't throw the other two parameters out.

 

[lmm1967]

Correct - get your alk up over the course of several days then follow bhodges advice above.

Leave Ca / Mg alone.