My tank parameters

Goodgreef · Jun 18, 2015

I have a 75 gallon reef, sps and lps. I run a RO NWB-110 skimmer and Turbo L2 algae scrubber as well as a BRS reactor with carbon. I dose BRS 2 part. I had an Aquarium Water Testing kit I got from a group buy I thought I would try out. As shown below, my Potassium is low as is my Iodine. My calcium is high as is my Magnesium. Currently I dose 30ml of Cal and Alk a day and 6ml of magnesium. I am going to reduce the Cal and Alk to around 27ml and magnesium will be off totally for a week or so and then I'll put it at around 2ml. I use Reef Crystals which I understand are high in Mag anyway. Im guessing the high level of magnesium may also be making Cal and Alk hang around without as much uptake, thus part of the reason they are a little higher than I'd like. I'd prefer my alk closer to 3.2 meq/l. I will have to start dosing and testing for potassium which I currently don't do and have never done. Also looks like I may need to dose some iodine too, which I am hesitant of as it is nearly impossible to test at home. The molybdenum is what I find most odd. I dose Nualgi 2 ml every 5 days. I wonder if Nualgi contains it, or BRS 2 part. I dose Acropower every 2 weeks. Those are the only things I ever dose. Anyone have further thoughts or critiques on my assessment?

Randy Holmes-Farley · Jun 19, 2015

FWIW, some AWT testing in the past hasn't appeared to be especially accurate, and that has appeared to me to include potassium. I do not know if they have improved their methods, but I'm skeptical that it is as low as stated. I'd get a different test evaluation before doubling the potassium level.

I'm not convinced that iodine is useful to supplement for most reefers, but when not dosing (as I do not), it will normally be depleted as organisms such as algae consume it. If you dose it, do it as an experiment with an eye toward whether anything living int he tank improves, not just to maintain a number.

Calcium and alk are fine, but letting them decline a bit is also fine. I agree I'd stop dosing magnesium for now.

The molybdenum almost certainly comes in with Nualgi, but that may not be your only source. Do you think it is useful for you?

Goodgreef · Jun 19, 2015

Thanks for the info. I had read about AWT not having great reliability. I will pick up a red sea K test and see what it shows. My red sea Mag test falls in line with the AWT result. I may just ignore the iodine. Nualgi has been amazing for my tank. I was skeptical and stopped dosing it a few months ago. I got a layer of green algae that started growing on my sand and had to clean my glass every 3rd day. My nitrates also went up to around 15. I started dosing it again and the green algae greatly declined after 1 dose, rarely have to clean my glass and nitrates dropped. Perhaps I will drop dosing now to 1ml every 5 days and do smaller more frequent water changes to help keep the molybdenum down.

Randy Holmes-Farley · Jun 19, 2015

Yes, adding sodium silicate has the same effect without any trace element or nitrate added: more diatoms grow and less green algae.

GainesvilleReef · Jun 19, 2015

My AWT tests always had low potassium, high moly, and high mag. I think they have some issues at AWT. I can not recommend doing anything based on their tests. I have had much better luck with Triton

Goodgreef · Jun 19, 2015

Randy Holmes-Farley said:
Yes, adding sodium silicate has the same effect without any trace element or nitrate added: more diatoms grow and less green algae.

I'm going to do a Triton test in a few weeks and if that confirms the Molybdenum level I'll be studying up and switching to the sodium silicate. Thanks Gainesville for the info, I guess there is a reason AWT kinda of stopped being talked about.

Randy Holmes-Farley · Jun 20, 2015

Here's a link to a paper of mine where I discuss sodium silicate, and I still dose it for sponges and such:

http://advancedaquarist.com/issues/jan2003/feature.htm

reefingnoob · Jun 20, 2015

For your pottasium test kit may I recommend selifert instead of redsea? It's much easier with good accuracy. Redsea is so tedious I gave up just after one test!

Goodgreef · Jun 20, 2015

reefingnoob said:
For your pottasium test kit may I recommend selifert instead of redsea? It's much easier with good accuracy. Redsea is so tedious I gave up just after one test!

Too late. Already ordered it online haha. I'll give it a go and may switch if I can't stand it. Anyone have expierence with the Elos Potassium test? That's the only one my LFSs have.

Update: Local reefer has a review of the Elos online. I think I'll pass unless it's changed since 2011.