Just don't understand whats going on

[Mooka151]

Short story, short. Tank is about 3 years old. Everything was fine and doing great. Had a tang that out of nowhere decided he liked nip a my duncan colony. In attempt to remove said tang I had to dam near take every rock out of my tank (placed in tubs with tank water). Anyway shortly after the rockwork being removed and reset I started to have issues with my sand turning green, where as before I had no issue.

Prior to moving the rocks I would do weekly 15% water changes and vac the sand on one side of the tank, the next week I would do the same and vac the other side of the tank. In all I would estimate that Im only reaching 30-40% of the sandbed as the rest is under rock. I would clean my glass ever 5-6 days (hardly noticeable film on glass).

Once sand started to turn green, growth on glass (brown) also exploded, I now have to clean the glass every 1-2 days. I havent changed maintenance schedule, using RODI water, TDS reads 0.0. I also have 40-45 nassarius snails.

This all started on May 28th. When I clean the sand the ugly comes back in 2-3 days. Recently (2 weeks ago) I stopped cleaning the sand to see if it was something that would self regulate and resolve on its own.... no such luck.

Im at a loss and dont know what to attribute this to. All the fish and coral is doing GREAT just the ugly sandbed thats driving me nuts. I have attached a photo that shows what Im talking about as well as my water parameters.

Any input would be greatly appreciated.

120 gal display with 30 gal sump
Protein skimmer and GFO reactor
+/- 90 lbs or rock
Temp - 79-80
PH - 8.1-8.3 apex
salinity 35ppm refractometer & apex
Ammonia - 0
Nitrite - 0
Nitrate - 4-5 ppm
PO4 - 2 ppb hanna
Alkalinity - 9 hanna
Calcium - 430 hanna

 

[editour2]

To me the obvious answer is the removal of the rocks. This disturbed the sand beneath the rocks and leached possibly phosphates, debris and/or other elements into the water and set off some time of bloom. Do you have parameters before and after the removal of the rocks? I would do a large water change, utilize filter socks and gfo/gac reactors...changing the media every week until things clear up.

 

[nanoreefer22]

What he said

 

[Mooka151]

Agree 100% that I disturbed something in moving the rocks around. When i removes one of the rocks that was on the sandbed it released a strong low tied almost sulfur smell. I have been running socks and gfo. Peramters have been consistent before and after moving rocks with exception of immediately after moving rocks, but it?s been almost 2 months with weekly 15% water changes ect. Can a bloom last that long with good water perimeters ?

 

[nanoreefer22]

Definitely can. 15% weekly won?t remove enough water to get you where you want to be. Try a few much larger water changes (50%). It?s a lot of water but will help

 

[Mooka151]

I?ll give it a shot, would you continue to vac sand during water change or just stick to large water changes without disturbing sand.
Thanks again

 

[nanoreefer22]

Honestly, I never vac'd the sandbed but know people who have. I would wait for others to chime in.

 

[bonomo53]

I would just let it be if corals and fish are doing good. I wouldn't touch a 3 year old sandbed

 

[editour2]

I would just let it be if corals and fish are doing good. I wouldn't touch a 3 year old sandbed

I agree.....I have a 5 to 6 inch deep sand bed in my tank....all of my rockwork sits on pvc pedestals made when the tank was initially being set up. I have never cleaned the sand bed...however that's just me, (could be a good or bad thing). My DT was setup in 2011.

 

[Spartanwarrior]

in the right corner of the picture, under the coralline, the middle/bottom of the sandbed looks brownish...is that throughout the tank?

I ask, and this may be drastic, but there's a possibility you may have disturbed the DSB so much with the vac'ing and rock moving that it began to dieoff and its leaching tons of phosphates, ammonia, nitrites, etc into the tank. you no longer have all that good bacteria on at least half of the surface area in your tank. 3 years of growth in there when disturbed can be a devastating introduction of O2 to all the anaerobic bacteria, and various other chemicals. a dsb should be disturbed only on the surface. imo the lower 4" should be kept intact.
if there is a widespread dieoff, you may be best off replacing the entire sandbed imo and doing a mini cycle with new bacteria in a bottle, like One and Only or Biospira.

I only speak from experience from 3 years ago when I began my adventure into this hobby. its very difficult to restart a dead sandbed. I know from experience moving an established tank from a friends house to mine and not rinsing the sandbed prior to resetting. took almost 2 years for my nitrates to come down =(

 

[Mooka151]

Yes what you see in the right corner is throughout the whole tank but its actually green.
I dont have a deep sandbed, 2" +/-. I have always vac'ed the sandbed as part of my water changes and never had this issue. It wasnt until I disturbed the rocks that were resting on "virgin" sand. I defiantly disturbed something when I moved the rocks and water quality went down for a few days but after that everything was spot on and that was 2 months ago, corals are doing as great, coralline still growing like crazy, fish are happy and shrimp are breeding. ORP on Apex is reading 410, but not sure that I trust it, because Im not using ozone and my readings have gotten as high as 425.

I did a large water change yesterday and in the process vac'ed a corner of the tank as an experiment to compare an area that gets vac'ed to the rest of the tank. I will say I did see life, there was worms and what looked like large pods. I know that I cant see beneficial bacteria but there was life in the sand.