Am I Over Skimming?

[Dolmo5000]

Hello, I am currently observing a few issues with my tank that lead me to the hypothesis that it may be overskimming.
Symptoms are:
1. sps polyp extension is moderate to poor for a portion of the day
2. Growth is very slow to zero
3. Random sps frags wither away slowly (some acro, monti caps, encrusting monti, and favia also).

Reasoning for my hypothesis that it MAY be over skimming:

First, I have VERY good water quality:
1. nitrates= negligible
2. phosphates= <0.25ppm
3. Calcium= 420-440ppm
4. Alkalinity= 4.25meq/L or 11.5dkh
5. salinity= 1.025
6. Magnesium= 1410ppm

second, I have tons of good light, possibly even to much. Over the 48in 55g aquarium I have a 48in 6 bulb T5 fixture (6x54w bulbs) makes 5.9w/g

Third, I have going on 100g in the system including a large refugium with chaeto algae to avoid nutrient buildup

Fourth, I have a feric oxide reactor and run carbon in a reactor 24/7

Lastly, When I add a bit of Kents Coral-Vit polyp extension increases tons, but the skimmer takes it out within hours. The reason I can tell is for about 3 hours after I add it the skimmer makes very good skim the same color as the kent product. Then slows and polyp extension goes back down.

Am I over skimming? Its a 160 rated skimmer on what is prob 85-100g or water. I need some help/advice. Thanks in advance for any contributions!

 

[sirreal63]

The PO4 can limit calcification, you really need to get that number down. What are you using to measure it?

 

[jtmbtech]

Anytime my phosphates go over .16 I notice it in coral growth right away. It should be under .08.

 

[swcc]

your not over skimming... if cheato can grow your tank is eutrophic.

 

[Dolmo5000]

Thanks very much guys for your input. I guess I missed/spaced about the phosphate level. I'm currently using API to test (which I know is not very accurate/sensative), but I will be getting the Hanna calorimeter test for phosphate in Monday. That will improve my testing ability. I run about 1.5 times the suggested amount of phosban through a reactor. What else would you guys suggest ? Also, Since I have so much light, I have the fixture 16in above the water. Does this seem logical? Would you guys do it differently?

 

[swcc]

lower the alk if bleaching is occuring. this can sometimes be a cause of problems with sps.turn skimmer off for three hours when feeding the coral.

 

[sirreal63]

Not sure how often you change out the GFO, but it become exhausted very quickly with high PO4 levels. You don't have too much light so i wouldn't worry about that.

 

[swcc]

Oh, I know this may sound weird, but a tank that is great at nitrate reduction often has a po4 situation. I also would actually suggest you look at removing macro algae. macro seem to offer better help with nitrate than Po4. and really, if you could balance your tank with say 1-2ppm nitrate and no PO4 that would be better. Also lets not forget all algae also releases nutrients as well which may have an effect on coral.

 

[jtmbtech]

I ran over the recommended amount of gfo too so I assumed my phosphates were OK. After a year of struggling with poor growth and not begin able to keep spa I finally bought the red sea pro kit and found out my phosphates were really high! Running gfo phosban does not take care of it if not changed enough.

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[Dolmo5000]

Thank you very much guys. I do seem to remember reading something about the super low nitrates may potentially have a deficient phosphate reducing community. It sounds weird but, I have this huge fug and if not to have macro in it, what do I do? Any suggestions? Thanks.