MG levels undetectable

[PI Guy]

I am about 6 weeks into setting up a tank again. Ive been out of the hobby for about 8 years. Ive got a 90 gal with about 100 lbs of dead "Live" rock, a sand bed, and a sump with bio-balls. I have been preparing to start a reef, dosing Kalkwasser, adding MG, and Iodide. I have slowly added a lot of MG and still do not have a good level. I have put in a lot (1/4 gal maybe) of Kent Tech M. It was left over from my previous tank, but its my understanding it does not expire. I ended up putting 1/2 mg, 1/2 aquarium water in the test tube and still got a low reading. During this process, I got a brown algae (diatom) bloom. Coincidence? Timing of cycling the tank? Calcium level is also down, even while slow dripping the kalk (gone through about 10 gal in 2 1/2 weeks). Ph is 8.3. Thoughts?

 

[griss]

What test kits and how old are they? Sounds to me like your Mg supplement is either bad or the test kit is off. Do you have a LFS you can take a water sample to to get a second “opinion” on test results?

 

[kharmaguru]

I'm going with bad test kit.

 

[PI Guy]

It is a NYOS test kit, new, good reviews. Its one of those tests where you add a solution and based on whats left in the syringe, you calculate your level. I always used the whole syringe. Tonight I added a second syringe of solution and it did change color. So real low MG. Im guessing bad Tech M.

 

[PI Guy]

How much do you think I screwed up the tank by dumping that much bad additive into the tank?

 

[griss]

I would do a 100% water change with water mixed to 1.025 with a good commercial salt mix and stop adding stuff to the tank. Your Ca, Alk and Mg will be fine. I dont think anything you have done will have bad effects long term. As long as your pH stays at 8 or so dont worry about it yet.
Do 20% water changes every week for a month and then 10% from then on. You should not need to dose until you have animals in the tank that use Alk and Ca.
Then start the kalk and monitor Mg. You will probably need to add very little Mg and then only weekly.

This. You’ll probably be fine. As BrianD has said for years, the solution to pollution is dilution. Water changes.

 

[PI Guy]

thanks

 

[JohnL]

Test freshly mixed saltwater to verify your test kit.

I would do a 100% water change with water mixed to 1.025 with a good commercial salt mix and stop adding stuff to the tank. Your Ca, Alk and Mg will be fine. I dont think anything you have done will have bad effects long term. As long as your pH stays at 8 or so dont worry about it yet.
Do 20% water changes every week for a month and then 10% from then on. You should not need to dose until you have animals in the tank that use Alk and Ca.
Then start the kalk and monitor Mg. You will probably need to add very little Mg and then only weekly.

I agree with the above.