Parameters out of whack

[jasony816]

I have a 75 gallon tank with 30 gallong sump with ATI 6x54 sunpower and I think someting is wrong with my parameters or the Red Sea test kits are off. I was getting good growth and then suddenly I am getting some STN from base up from some of my corals not sure why, no bugs or anything as I dip and QT everything. I am also using biopellets, gfo (1/4 cup), carbon (1/4 cup), and kalk(ATO). I do weekly 10% water change and bi-weekly change out the gfo/carbon. Any recommendation as to what I am doing wrong would be great.

salinity: 1.025 - 1.026
temp: 77-79
ph: 7.8-8.1

Red sea test kit:
P04: 0
N03: 0
ALK: 10 - 10.8
Ca: 500
Mg: 1600

 

[swk]

Maybe too high of alkalinity if nitrates and po4 are truly zero. With low nutrient tanks it is recommended to stay within or slightly below NSW parameters.

I was running alk at 9.3 while
Carbon dosing and couldn't keep birdsnest alive to save my life and many pieces stn'd. Had poor color, slow growth etc. dropped alk to 7.3 and things have really turned around

 

[swk]

Mag and ca seem overly high as well. Maybe consider taking those down to nsw levels as well

 

[Breadman03]

I've read that high alk in a low nutrient system (ULNS), such as you appear to be running, can be problematic. That may be part of it.

 

[tripdad]

Get your mag and calcium in line and slowly! lower your alk to 7.5 - 8.0. Carbon dosing in an ULNS system causes problems with higher alk levels. One other side effect of carbon dosing can be much clearer water so sometimes light levels have to be adjusted for that compared to what some other tanks are running. I don't think your lights are too much though.

 

[jasony816]

How do I know if P04 and N03 is truly zero as I do have some algae like film but not hair algae. How would I lower alk/ca/mg? Dont do water changes or maybe do 10% every other week instead of 10% every week as I am using Reef Crystals.

 

[Breadman03]

Look into salt with lower levels. I'm currently using IO, but am going to switch to a different brand once I read into it a bit more.

 

[tripdad]

Go to the reef chemistry forum and do a search. Most of the time Randy or someone else has put the info out there for you. The calcium doesn't really concern me, jmo, but the mag being so high can indicate that something is out of whack. Please read Randy's articles on this relationship as he explains it way better than i ever could. Alk is easily adjusted by separate means. Usually the salt is the first place to look, I used reef crystals until I really tested the raw mix and saw how crazy high alk was, like 11.5 - 12.5. Check each batch as there are real quality control issues out there.