Alk / Cal / Mag - Issues

[BfishLpond78]

So I've had quite the battle with the big 3 this year.

Back story:

180-190 gallon total system. Mixed reef

I began adding corals slowly, mostly SPS. Things were going good, coloring up and growing. My weekly tests showed that Alk and Cal were being consumed so I started a light dosing regimen of 5ml's of each. My Alk/Cal were steady at 8.2 and 420 for a few weeks. Same results...good color and great growth.

The all the sudden it all went downhill...weird green/brown turf algae took a hold and my parameters plummeted. SPS lost color, tips started turning white and polyp extension was poor. NO3 and PO4 were undetectable.

When things went south Alk was 7.0 and Cal was 375. Mag has always been off the charts 1600+ (not sure why).

I have since brought my Alk/Cal up slowly...it's now 9.1 and 425. I'd like my Alk at 8.1-8.4. Currently dosing 50ml of each.

Should I drop the amount of Alk dosed or both Alk and cal to keep them balanced? Also, how do you reduce Mag???

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure there is any direct relationship between

"weird green/brown turf algae took a hold"

and

"my parameters plummeted."

since neither of those two should take up either calcium or alkalinity.

It is certainly possible that if nutrients (nitrate and phosphate) actually got too low (hard to tell from test kits) that those may be the reason for the suffering SPS.

I'd try to keep the alk steady, and if nutrients are very low, aim for 7-8.5 dKH, not higher, for fear of "burnt tips".

Calcium is really not critical, and 400-450 is a fine target range.

 

[BfishLpond78]

Thanks for the response Randy. I don't believe they were connected either, I just like to try and paint the best picture of the situation.

Any idea on the mag question?

 

[Randy Holmes-Farley Verified Community Expert]

The magnesium could be testing error. There is a lot of that for magnesium.

That said, it might also be high in the salt mix for some reason.

What mix and what salinity?

 

[BfishLpond78]

The magnesium could be testing error. There is a lot of that for magnesium.

That said, it might also be high in the salt mix for some reason.

What mix and what salinity?

I've been using the Instant Ocean Reef Crystals and mixing it to 35ppt

I've used 3 different test kits...going to try salifert tonight.

 

[Randy Holmes-Farley Verified Community Expert]

OK, let us know what you find.

 

[BfishLpond78]

Salifert put my Mag at 1450
and my Alk at 6.1!!!! Ugggghhhhhh!!!!

 

[Randy Holmes-Farley Verified Community Expert]

OK, so I'd just not worry about magnesium.

 

[BfishLpond78]

OK, so I'd just not worry about magnesium.

This is like an emotional roller coaster...I got one test telling me it was 9.1 and the other saying 6.1. This is maddening!!