Need help

[Gazza]

My tank has been up and running for almost two years. I am still new and learning

a couple of month ago I started having this wired looking alge that is both green/orange brown in color 

I started using nopox , I have a Red Sea 260 and I was dosing nopox 3 ml daily

today I found almost all my fish dead with the expectation of two clowns and cleaner shrimp and a tang 

my water parameters are 

dkh 9’.5

ph 8.2 

nitrate 50 ( I know it’s high so I am cutting on food today) and reducing quantities 

phosphate 0.1 

Ammonia 0

nitrite 0.1 

i also tried chemiclean with no effect whatsoever 

your help is much appreciated 

[Timfish]

So sorry to hear your loss! :(

 

It's hard to say what happened with the information you've provided but my guess is something dropped the oxygen levels short term.  Do you have any corals or other invertabrates?   If so how are they doing?  Is it possible any type of cleaning solution got into your tank?

 

As far as dealing with the various nuisance algae type/species I only use manual removal and have hardly any fish related deaths.  It seems unlikely to me what you've done to deal with the algae has caused your fish dieoff.  FWIW, chemiclean only works on cyanobacteria.  If you have some other type of nuisance algae it has little effect.  I would caution against using it repeatedly as there is risk of creating a resitant superstrain of cyano.

[Gazza]

Thank you so much for helping out 

I used redsea nopox 3ml daily and that might have been the reason for fish dying 

I have an corals and they are all doing well , no issues there 

will continue trying to remove manually and increase frequency of water changes 

if you have any other advice kindly share , I am willing to try anything to get this issue resolved with the least casualty 

thanks again , much appreciated 

[victoly]

any new fish added lately?

[Gazza]

No, nothing new for over 5 month 

[victoly]

any new frags or inverts? Was there anything different about the way the fish looked?

 

[Reburn]

nopox is carbon dosing.  like vinegar or vodka.  Likely over did it and depleted oxygen which caused fish to sufficate.  You should look up carbon dosing on R2R or RC.

[jolt]

Chemiclean has been known to kill fish from oxygen depletion as well

[Gazza]

My tank is over taken by green alge 

this is a pic with daylight lighting only

what do you think guys ? 

[victoly]

Honestly that doesnt look too bad. Scrape the glass. Top off your sediment with new sand, and add in more cleanup crew like snails and urchins and rabbitfish. 

Maybe try to waterchange your way out of 50 ppm nitrates also. It's not hugely problematic, but its probably contributing. 

Adding more coral will also take your attention off the algae. 

Another thing that helps is to run bluer lights, even though the algae is still there its not as visible. 

 

[Gazza]

Thanks , will try your suggestions 

much appreciated 

[Timfish]

I agree, that doesn't look bad at all.  for the sand you can siphon off the top layer that has algae growing on if and soak in H2O2 for a day or so, rinse then return to the tank.  More corals will compete with the algae for nutrients also.    To get a better understanding of the role of Dissolved Organic Carbon, DOC (aka carbon dosing) in reef systems read Forest ROhwer's "COrals Reefs in the Microbial Seas" Kindle version is !$10, papaerback is ~$20.  I see you have a pink short spine urchin. Being only a ~60-70 gallon system if you get more urchins look for small ones and be ready to rehome them, your system may not be able to support more than one long term.

[Gazza]

Thanks guys 

really appreciate all your help and input 

will update this post in a month to two , to show progress

thanks again