Hi everyone

I am looking to get some help with my tank. I'm experiencing some STN and coral bleaching on my SPS. All other corals look great.

Tank Volume: 70 gallons
Lights: 6 x T5HO (1 bulb changed per month)
Photoperiod: Currently at 5 hours for all 6 bulbs
Water movement: 4 x MP10 (80%), Hydor 1400 behind rocks, Eheim 1262 return
Protein Skimmer: Bubble Magus NAC5e (rated at 80 GAL - 120 GAL)
Barebottom reef techniques
Tank was started mid December 2012. All corals and rock transferred from my other barebottom tank that was started in June 2012.

Maintenance schedule
- clean filter sock after blasting rocks with turkey baster (daily)
- clean protein skimmer cup (full cup daily wet skim)
- wipe tank walls down (daily)
- 5 gallon water change with treated tap water (weekly), siphon out detritus that collects at the bottom
- test parameters (check ato, dosing mix) weekly

Parameters
- Salinity 1.026 (refractometer)
- Nitrate 0 (API)
- Phosphate 0.02ppm (Hanna ULR)
- Calcium 450 (Salifert)
- Alkalinity 8 (Hanna)
- Magnesium ??
- PH ??
- Temperature 25 celsius

Stock list
- 2 clownfish
- 1 blue hippo tang
- 1 tailspot blenny
- 1 lawnmower blenny
- 1 scooter blenny
- 2 green chromis
- 2 yellow chromis
- 3 peppermint shrimp
- 2 mexican turbo snails

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I was dealing with cyano and contributed this to the fact that my lights were on for 8 hours each day. Plus I was overfeeding the tank (did not defrost frozen before feeding fish). To combat it, I have been blowing my rocks off on a regular basis, and dosing one drop of Zeobac per day. It is working. There is a problem with red hair algae though.

This green stag colony started bleaching from the middle of the colony out. At first I thought it was AEFW but it wasn't little circles that disappeared (never verified or checked). Now as you can see, entire branches are bleached. What is strange is that the polyps are still there and at night, I get full polyp extension.


This acropora colony (sorry don't know what type it is) started dying out at the tips. You can see the algae growing on various tips. My ALK levels were consistent. I'm slowing trying to bring the levels up higher to 8.5 - 9 DKH range though.




Any help would be appreciated. I do have plans to switch to an RO system, but that won't be for another couple months. I do feed my corals with reef roids 2 times a week.

Here is a full tank shot.