Ideal Water Parameters for SPS or Mixed Reef Tank
 

FWIW, I wouldn't be trusting a Hagen test kit for the most important parameter in your tank (alkalinity). Hanna and Salifert both make more reliable kits. I use Salifert for calcium, Salifert and Hanna for alk, Salifert and Red Sea Pro for Mg and NO3, Hanna for PO4, Hanna handheld digital meter for pH. Temp I use a NIST certified thermometer (about $50 on Amazon) which I use to calibrate cheap thermometers that stay in the tank.

IME, for best SPS growth, you're best off running higher than natural parameters:

Ca: 440 ppm ish
Alk 8-9 dKH
Mg 1300-1400 ppm ish
NO3 2-10 ppm
PO4 0.08-0.1 ppm ish
pH 8.4-8.5
Temp: 81-82F



For best color, closer to natural seawater parameters seem to be better.

Ca 400-410 ppm
Alk 6.8-7.2 dKH
Mg 1200-1300 pm
NO3 0.5-2 ppm
PO4 0.001-0.05 ppm
pH 8.1-8.3
Temp 78-79F

Thanks Mindy! I definitely agree with not using the Hagen test kit. I have ordered the Salifert and Red Sea Reef Pro test kits as the pre-boxing day sales at the LFS emptied them out. There is so much conflicting information out on the internet for these parameters, although I don't mind tweaking, I don't want my tank to suffer.

Just make sure you don't tweak too much or too often. Sps take about 2-3 weeks to react (unless you do something really bad lol).

Fair enough! I was using Instant Ocean salt, however I picked up a couple pails of Reef Crystals today. Planning on slowly transitioning for the extra trace elements. What are you currently running for you Cal / Alk / Mag levels? I definitely don't want to tweak and have my sps go sideways. Things are a little higher then I would like, trying to get to the sweet spot and setup my 2-part doser.

Ca, alk, and Mg levels need to reflect NO3 and PO4. If NO3 and PO4 are ultra low or undetectable you can't have high alk or you will get burned tips.

For the first 18 months, I was really struggling with ultra low nutrients. I tried a bunch of things to raise nutrients, but couldn't find the sweet spot, so I had to keep the big three at natural seawater levels. Just recently I started using Pohls Xtra which contains ammonia, nitrate, and amino acids. This was the magic ingredient for me and I'm finally able to get some NO3 and PO4 readings on the test kits, so I slowly let Ca, alk and the rest of the parameters rise up a bit. Currently sitting at Ca 430, and alk 8.2.

That makes sense! Thanks for the wealth of knowledge on the topic :biggrin:

You're welcome. You'll find a lot of opinions on the topic, this seems to be the most up-to-date knowledge. Of course you'll always find a Joe Reefer that has "zero" NO3 and PO4, and keeps his alk at 12 dKH. There are always explanations for this too, such as maybe Joe Reefer's test kits suck, or maybe Joe Reefer feeds lots, but has great nutrient removal so the water column has low nutrients, but the corals get lots. It's more of a "look at the corals" thing - true ultra low nutrients will have pale SPS. Basically, pale SPS can't handle high alk, nor high light. Oh yeah, don't forget light, if they corals are pale from ultra low nutrients, they will not appreciate high light.

I think everyone on here would agree that patience and stability is the key meaning if your alk is at 8 keep it there. If your params are bouncing around sps corals don't seem to do much. But once consistent then there's no stopping the growth. Time heals all... it's funny sometimes you think the tank is dialed in as your weekly testing the alk and everything is in check then you do a monthly check on ca and find out is at 360, mg is not measurable lol.

Weekly WC and stable parameters is what we strive to achieve, you can always tweek the other stuff later.

So true! I have been trying to dial it in and keep them stable. I have been doing weekly tests to see the amount my tank is consuming as I bought a bunch of frags over Christmas. I just don't want to shock my tank and only have a single polyp left with burnt tips :lol: