long post, but i'm trying to put all the info in it i can so you have as complete a pic as possible. please bear with me!!!

So, i've been maintaining my gf's dad's tank for them at their house. i set it up for him almost exactly a year ago and we gave it to him as an xmas gift.

here's the basics:
nc12 w/ 4bulb t5 light (fish needit)
external overflow to 3.5 gal sump w/ chaeto and light (on 24/7)
approx 12lbs LR and LS
nano skimmer
50watt stealth heater
1 clownfish (approx 1.5")
2 emerald crabs (to get rid of red bubble)
1 sally lightfoot (that the LFS convinced him to get)
4-5 nass
1 trochus
2 cerriths
dozens of stomatellas and collinistas
zoas/palys, gsp, xenia, shrooms, duncan, hammer

parameters (all taken in the evening, approx 2 hours before lights out using API):

11/11
pH 8.2
dKH 6
Ca 360
Mg 1085-1110 (salifert)
Am 0
NO2 0
NO3 0-5

Did not dose anything that day.

11/15
pH 8.2
dKH 6
Ca 360
Mg 1085-1110 (salifert)
Am 0
NO2 0
NO3 0-5

I dosed approx 1/8 tsp of seachem Alk and Ca and approx 4ml of Brightwell Magnesion.

11/19
pH 8.2
dKH 7
Ca 380
Mg 1200 (salifert)
Am 0
NO2 0
NO3 0-5

Did a 2.5gal water change and re-tested w/ same results. Again i dosed 1/8 tsp Alk and CA and 2ml of Mg. (mixed separately and added about 5 min apart).

Up until about 5-6 months ago, the tank was doing pretty well. lots of growth, good colors, coralline growing everywhere, etc etc. Then the red bubble algae started appearing and it quickly infested the tank. At that time i built the overflow and set up the sump and skimmer, w/ chaeto and light. began manual removal of as much red bubbles as i could. Then a couple months later i bumped up # of water changes to 3/mo. (up from 1-2/mo [i know, bad]) 1 gal each.

then about 4-5 months ago the tank started to decline. zoas receded/melted away. the gsp closed up for months and actually started to recede, the hammer rarely fully inflated, the duncan barely came out, the red bubble algae still spreading.

finally about 2 months ago they got a couple emerald crabs (i'd been telling them to avoid them b/c of the potential risk- but they totally cleared out all the red bubble algae). I increased water changes to 4/mo. I notice when i change the water there's a oily film on teh water surface. they only feed every 3rd day, alternating btwn pellets and frozen.

about 1 month ago things started to improve, the gsp finally started coming out after being closed for months, the duncan was coming out and the hammer was doing better. awesome i thought, so i added 1 stalk of my xenia to his tank and three shrooms about 3 weeks ago.

xenia was pulsing and stuff was opening more and more. but the xenia didn't look as good/full as it did in my tank. which finally led me to test the water on 11/11. When i was over at the house last night, the xenia was in the process of melting, the duncan was closed up tight, the zoas were close, the gsp was closed. the shrooms looked like they were reaching up for the light (which were on).

i can't figure it out... what the heck is going on w/ the tank??? it's frustrating me like crazy! :s

thanks for reading thru this novel. HELP!

Edit to say:
mods feel free to move this if it's in the wrong place

EZ! Sounds like to me.....new light bulbs! Ez fix bulbs lose their power after 7months u can't see it with the naked eye

doh! sorry, forgot to mention i changed out the bulbs about 4-5 months ago. KZ fiji purple, ATI blue+ and ATI something else. I thought it might impact the bubble algae.

also, would lighting cause the xenia to melt??

ditto check the bulbs. Never mind lol.

Has anyone messed with the flow in the tank?

good point...forgot to mention that too! lol.

flow has been the same:

K-nano under the modular skimmer pointing to the front corner (left corner if facing tank), and a nc24 stock pump for the return, w/ a hydor flow attachment.

Ur stats seem decent....ur kh can be higher (11ish). What kind of tank is it? U have a protein skimmer?

that's why it's making me nuts...


it's a 12gal nano cube open top (w/ a 3.5gal sump).

whats the salinity and temp at?

*smacks forehead* sorry!!

SG is 1.025-1.026

Temp ranges btwn 79-82

Could it be something in the air? A plug in air freshener or something like that? Not sure if it would have that sort of effect on the tank...just trying to brainstorm

Also check for stray voltage. In that size tank may be hard to do so just go out and spend the $10 on a grounding probe. Should be doing that anyway. And do try that MH light you mentioned on SCNRS

+1, control nutrients and remove manually and with the emeralds if they are useful and it will get back on track. check your source water.

I'll look for a ground probe tomorrow. And I'm changing out the light to mh tonite. And he does have a protien skimmer running in the sump (and chemipure elite).

I know there aren't plug in air fresheners in that room. But I did see one in the bathroom outside the room about 30 ft from the tank. But that was about two months ago and it hasn't been there for at least a few weeks.

Thanks everyone I really appreciate the input. Please continue putting ideas out there.