Best approach to dealing with low Alk #'s

[WiscoFishNut]

Hey folks, so my tank is finally at the point where I'm seeing some pretty major swings in the test #'s. I've got around 30 different smaller coral pieces, mostly softies, LPS, and a half dozen SPS (monitporas and acroporas).

Here are some details. Please let me know if more info is needed

Tank 60 g cube, 20g sump - total volume ~71g filled
Dosing - nothing to this point
Salinity - 1.025
Temp - 79-80
Half butt chaeto in fuge section running lights @24 hours constant
Weekly 15g water changes
Feeding - just the fish - pellets at lunch, mix of frozen mysis shrimp and Rod's at dinner time
CUC - army of snails, hermits (10), fuzzy chitons (3), and a scarlet skunk cleaner shrimp (the CUC was recently expanded due to GHA and turf algae getting out of control)
Water source - RO only, no RODI. TDS @1 ppm. A full RODI is on my list for sure, just waiting on BRS to get the 6 stage kits back in stock. I may just bite the bullet and get the 7 stage.
Tank age - wet since 10/28/2019

Typical water parameters
Alk : 8.3
Ca : 415
Mg : 1380 - 1400
pH : 8.25
Salinity : 1.025
PO4 : .05 - 0
NO3 : 5-10ppm

After adding quite a few corals we are here -

Most recent - 7 days since last WC
Alk : 6.6!!! (I ran the test 3 times with a Hanna checker and a Salifert test for sanity over the course of 48 hours)
Ca : 390
Mg : 1360
pH : 8.2
Salinity : 1.024 (remedied this. A power outage caused some ATO issues that made it swing slightly)
PO4 : .18
NO3 : 15ppm

I plan on doing tests every other day for the next 14 days to see where the #'s go, but ultimately it looks like I need to do something about the Alk #'s. I could definitely use some advice so I don't screw this up lol. I was pretty surprised the Ca level wasn't lower as typically after 7-8 days it would be 375'ish. Only ran the Ca test once because its a pain in the butt..

 

[Rybren]

Calcium should only drop by 18-20ppm for each 2.8dKH of alk consumed, so you really shouldn't see huge changes in it.

I'd say you're ready to start dosing. There are lots of option to choose from ranging from Kalkwasser to one of the many 2-parts, to a number of other options. Randy has some great articles in the stickies that discuss the various methods.

Focus on testing alk initially as Calcium and Magnesium tend to move slowly.

 

[WiscoFishNut]

Calcium should only drop by 18-20ppm for each 2.8dKH of alk consumed, so you really shouldn't see huge changes in it.

I'd say you're ready to start dosing. There are lots of option to choose from ranging from Kalkwasser to one of the many 2-parts, to a number of other options. Randy has some great articles in the stickies that discuss the various methods.

Focus on testing alk initially as Calcium and Magnesium tend to move slowly.

Thanks @Rybren, I'll take a look at the articles. I'm definitely looking for something conservative and lower maintenance if possible.

 

[X-37B]

I would test alk daily at the same time to deterime daily consumption.
Then dose 2 part in equal amounts. I like esv 2 part.
Then continue to test daily.
It wont take long to determine the daily 2 part dosing.
I dose in the morning then test the next morning and dose again.

 

[Randy Holmes-Farley Verified Community Expert]

I agree a two part is a good way to start dosing.

 

[WiscoFishNut]

I agree a two part is a good way to start dosing.

Would a product like Tropic Marin All-For-Reef be a good choice, or avoid it since it contains Mg as well? I see they make a DIY version that splits things out.

I saw ESV 2 part mentioned as well, but I'm not sure which specific product would be appropriate. The Kalkwasser powder maybe?

 

[ScottB]

I am long time user of ESV 2-part for ALK and Ca. Given you are changing water 15% per week you would not need to worry about Mg.

I dose equal amounts (as recommended) but really only measure ALK. Measuring Ca is a waste of time as it is always very high.

You could begin dosing manually. As your consumption increases, it will at some point make sense to use a doser to "smooth out" your ALK levels.

 

[Randy Holmes-Farley Verified Community Expert]

Would a product like Tropic Marin All-For-Reef be a good choice, or avoid it since it contains Mg as well? I see they make a DIY version that splits things out.

I saw ESV 2 part mentioned as well, but I'm not sure which specific product would be appropriate. The Kalkwasser powder maybe?

ESV two part means B-ionic. It is a fine choice, as are other two parts. It also contains magnesium, as does my DIY two part. Magnesium is not critical at the early stages of dosing.

My suggestion is to not complicate things yet with formate dosing, which is All for Reef. Deciding how much to dose seems, according to Tropic Marin, more complicated than is necessary at this stage. I'm not totally convinced what they are saying is true, but if we accept it, I'm not a big fan for folks trying to understand how much to dose.

 

[WiscoFishNut]

ESV two part means B-ionic. It is a fine choice, as are other two parts. It also contains magnesium, as does my DIY two part. Magnesium is not critical at the early stages of dosing.

My suggestion is to not complicate things yet with formate dosing, which is All for Reef. Deciding how much to dose seems, according to Tropic Marin, more complicated than is necessary at this stage. I'm not totally convinced what they are saying is true, but if we accept it, I'm not a big fan for folks trying to understand how much to dose.

ESV B-ionic it is, thanks sir!