In my quest to discover why some of my corals were looking pale (in one case very pale indeed) with poor or non existent polyp extension I decided to send a sample of tank water off to Triton for an ICP-OES (which stands for Inductively Coupled Plasma-Atomic Emission Spectroscopy) analysis. I must admit that I had actually intended to do this anyway when the tank reached the 6 month mark just because I was curious as to what it would tell me about my water quality.
At the same time as sending off the sample I did a whole round of testing myself. The intention being that I could compare both results and see if my test kits (not to mention my testing technique) were up to scratch.
Here are the results from my testing performed on the 18th April 2017.
Specific gravity: 1.026 (51.7mS according to my conductivity probe)
Alkalinity: 7.0dKH (Salifert)
Calcium: 410ppm (Salifert)
Magnesium: 1272ppm (Salifert)
Potassium: 390ppm (Salifert)
Strontium: 0-3 (Salifert)
Nitrate: undetecable (Salifert)
Phosphate: undetectable (Hanna phosphate)
Iodide: <0.01 (Salifert)
Iodate: <0.03 (Salifert)
...and here are the ICO-OES results.
So what do the above results tell me? Well, the obvious issue that immediately jumps out is the elevated tin (Sn) level. Eeek! Where on earth did that come from? I have read that a possible source for tin could be the glass (as molten tin is used to "float" the glass on during it's manufacture). Other than that, something could be rusty and contaminating the system but I'm at a loss as to what it could be, all the equipment was bought new and there's nothing obviously rusting as far as I can see.
Apart from tin, I don't think the rest of the results look too bad really, pretty much as I expected. My tests are not that far off which is good to know (with the possible exception of Strontium which is low with the Salifert test kit but actually at an acceptable level according to Triton). My phosphate level is surprisingly low despite the increased fish load and extra feedings. Triton recommends feeding more and/or reducing the amount of phosphate remover used. As I don't use any remover that's going to be difficult to do but I do intend to feed more to my corals.
Ca: 410 434
Mg: 1272 1258
K: 390 386
Sr: 0-3 7.06
Iodide/Iodate: <0.01/0.03 0
PO4: undetectable 0.006
So what now? Well I'm going to continue performing water changes as normal, maybe change out a little more in the next a few weeks. Triton recommends 6 x 15%, but they are probably assuming that I don't perform water changes at all which is certainly not the case. I popped a polyfilter into the sump for good measure mainly because I had one to hand (from years ago, I hope they don't 'go off'?) and surely it can't hurt. I also intend to start dosing iodine again.
Just before sending off the water sample to Triton as reported in a previous post, I also reduced the intensity of my lighting. It's been 14 days now and I do think that there has been an improvement in the corals, the colours look a tiny bit better and the polyps are starting to extend again. Perhaps the lighting was the main issue? I am hopeful that things will continue to improve. Now I just need to get rid of all that tin....
Photos to follow on Monday with the full May update.
Hi, my name is Lisa and I live in Derby, UK. I am a self-confessed reefaholic!