Diagnose slow decline

[syncro]

Over the past 3 months my tank has slowly changed for the worse. I was hoping someone could suggest what to do next.

Symptoms
- amphipod population slowly declined
- chaeto has slowly died off
- cyano and green hair algae on sandbed
- no algae growth on glass anymore (good for maintenance but doesn't seem healthy)
- 2 snails have died
- protein skimmer pulling out less gunk (also more volatile, harder to adjust)

Changes
- added haddoni carpet anemone
- added 2 bengaii cardinals
- changed carbon brands (MarineLand to Eli's caco3 ROX style carbon)
- changed carbon from floating in bag to carbon reactor
- new bucket of salt, same brand
- chemical warfare between haddoni and rbta

The current livestock all appear healthy and eating well, but it feels they are just better coping with an underlying problem that the simpler organisms (pods, chaeto) did not.

Any suggestions? Thanks!

Tank: 40G, 12 months old
Lighting: 250W MH on 8hrs/day, 4 x T5s on 10hrs/day
Temp: 24.3 - 24.6*C
Salinity: 35ppt w/ ATO
Ammmonia: 0, nitrite: 0, nitrate: 0, pH: 8.4
Filtration: Skimmer, 3.5" DSB, live rock, carbon
Livestock: carpet, RBTA, GSP, occelaris clownfish, porcelain crabs, sexy shrimp, snails, hermit crab, dragons breath, chaeto
Maintenance: Weekly 12% water changes with RO/DI water mixed for at least 24 hours
Feeding: Pacifica Plankton and NLS pellets

[Ross]

If that pic is current, I'd start by cleaning the power head and returning some flow to the tank.

[Proteus]

Do you use zeo, Biopellets , or prodibio

What's phosphates at
How muck live rock u have
Like Ross said. Your power head is in bad need of clean. Dip it in peroxide too.

But tank does look good

[syncro]

Thanks Ross. The filter floss around the powerhead is changed every other week and the powerhead is just run at a higher speed to compensate. It has been running like this for the past year so not sure if it is related to the recent problems. I'll remove it to see if it helps. Thanks again.

[syncro]

I'm not running zeo, biopellets or prodibio. No chemical filtration other than carbon. Good question - some symptoms are similar to the ULNS systems.

Live rock: about twice what you can see, the other half is in the sump.

Phosphates: i'll measure. Thanks Titus.

[Ross]

Perhaps the deep sand bed is contributing to your issues also? Are you disturbing it at all? vacuuming it or stirring it?

[11purewater]

maybe take the carbon out and see or rather smell the water.May be H2S gas in your sandbed.Also nice tank btw how much biological filtration do you have?live rock etc.

[reefwars]

- amphipod population slowly declined
- chaeto has slowly died off
- cyano and green hair algae on sandbed
- no algae growth on glass anymore (good for maintenance but doesn't seem healthy)
- 2 snails have died
- protein skimmer pulling out less gunk (also more volatile, harder to adjust)

is it possible your tank is contaminated somehow like the silicone??

[Proteus]

Be nice to see more rock. As for h2s. A little peroxide will help that. When I ran a 3" sanded I had h2s. But I'm guessing ha and cyano may be from po4. Some rowaphos would fix that.

I can't grow maco algea either. Which is fine buy me

[11purewater]

Could be just one of those weird cycles a tank goes through naturally.panic =spend money.If your parameters are good maybe just be patient and diligent with your husbandry,I know losing livestock sucks but thats all part of it.Nobody has all there original clean up crew anymore.