Got ATI results back - need guidance

[fluidimagery]

My tank has taken a bit of a back burner lately. I've still been doing my bi-weekly 15gal water changes on my RedSea 625xxl using Tropic Marin Pro salt, fish get fed on an auto feeder using pellets and I feed frozen a once or twice a week. The softies and LPS seem fine, my SPS have pretty much deteriorated - few colonies left but they're not looking so great and growth has been slow. Not much nuisance Algae to speak of - did go through a Dino phase that was tough but using the dirty method and UV Filter was able to get rid of it.

Salt: Tropic Marin Pro
Filtration: Octopus Skimmer, Marine Pure balls in the media baskets, Carbon in a media bag - passive filtration, UV Filter runs 24/7, Algae Scrubber
Bare Bottom Tank
Was dosing Calc, Alk and Mag using a GHL doser but stopped about a week ago (after sending in the water samples)
RODI - measuring 0 on the TDS.

Anyway, I sent an ATI test in to get a baseline and below are the results.

Tank: https://lab.atiaquaristik.com/share/24164479558359e8ea0d

RODI: https://lab.atiaquaristik.com/share/bec10c133ebe76ad7d93

Where should I begin?

 

[GabeM]

I would start with slowly raising your salinity to 35 as it is borderline dangerously low for corals. Your phosphate is really high and aluminium. Your alk is almost dangerously low.

Good on you for doing an ICP test but are you testing your water weekly? Most of this would be detected with regular testing.

 

[fluidimagery]

Thanks, I'll run some GFO, get the Alk up and check on the Salinity. Just ordered a new Hanna digital salinity meter. My 10+ yr old refractometer is reading 33 and seems calibrated. What is the best way to get the Aluminium down and where would it be coming from?

 

[brmreefer]

In regards to the aluminum. Was Phosguard ever used in this system? Phosguard is aluminum oxide and is used to absorb phosphate and silicates. Not sure how to bring it down, other than water changes or maybe carbon.

 

[Randy Holmes-Farley Verified Community Expert]

Assuming the ATI values are correct (ICP is not a guarantee of 100% accuracy)...

I agree that salinity is very low and I'd raise it.

Stop adding magnesium as it is going to get pretty high when you raise salinity.

Calcium and potassium are low now but will be fine after raising salinity.

Phosphate is fairly high, but I'm not sure if lowering it will help the SPS.

You might experiment with dosing iodide and with a trace element supplement to see if it helps your tank.

I don't think the aluminum is high enough to cause problems.

 

[GabeM]

Thanks, I'll run some GFO, get the Alk up and check on the Salinity. Just ordered a new Hanna digital salinity meter. My 10+ yr old refractometer is reading 33 and seems calibrated. What is the best way to get the Aluminium down and where would it be coming from?

to @Randy Holmes-Farley's point I think that fixing the salinity should be your first priority and to add to that GFO can act very quickly if not implemented correctly and may stress your corals further.

If I were you I would double check the readings for Salinity, PO4 and NO3 with home test kits since these tests are not part of ICP testing (not 100% sure in Salinity tbh) and are tested at ATI outside of ICP testing.

If your salinity is truly that low you can do water changes or add salt to your top-off water, I would do both in this order:

1. Remove 20 G and then add 20 G @ 38 ppt
In order to reach 30.97 ppt.

2. Remove 20 G and then add 20 G @ 38 ppt
In order to reach 31.82 ppt.

3. Remove 20 G and then add 20 G @ 38 ppt
In order to reach 32.57 ppt.

4. Remove 20 G and then add 20 G @ 38 ppt
In order to reach 33.23 ppt.

5. Add 35ppt new saltwater to ATO and test daily until it reaches 35ppt.

Probably wait 1-2 days between water changes. This gives you the benefit of gradually fixing many of the parameters out of range in your water and not shocking corals while fixing your salinity.

Always make changes gradually and only change 1 thing at a time