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.

[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]

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

[HaZRaTTy]

I was under the assumption that cheato will feed on excess Phos/Nit. Also what type of bulbs and how high from the surface are they.

Your cheato however will die off from a lack of nutrients (lucky for you its easy to find someone giving away the stuff to replace)

If your bulbs are actually a year old I would begin with replacing those, also would cut back to a bi-weekly WC

H2S - Would only be a huge factor if you are stirring and disrupting the sand bed how long has your tank been setup for if it hasn't been a very long time I doubt you would have enough build up to cause a problem

What type of CUC do you have snail wise? Was it Turbo's that have died tanks really tend to show when one of those buggers die.

I also doubt that if your tank was built by any tank builder they would be not using a GE product especially if it was built recently. If you're still in doubt you could always call but chances are if your tank has been running for some time without problems from the start you're in the clear.

What are all your other water parameters?

Try to flood us with information the more you give, the more accurate response you'll likely to get.