Crabs dying...help please?

[Gordinho80]

posting thing for my brother-in-law...

he has a 120gal SW setup with fish only...no coral/live rock/live sand etc...

he has 3 crabs in this tank. they have been in the tank for approx 6 months now with no issues...recently, he added 2 small maroon clowns and a starfish to the tank...now, one of the crabs has died, 1 is barely moving and is even upside down most of the time, and the other, the largest, has become very lethargic as well...

in the passed 2 weeks, since these new additions have been brought to the tank, there has been an increase in brown algae on the rocks, substrate, and the piping for the sump...

he has more than enough water movement with undergravel jets...his lights are a 50/50 bulb and an atnic bulb. the lights are on for 3 hrs at a time twice daily...

he does feed them twice a day and there have been times where he has noticed left over food...i advised that he reduce feedings to once daily and to monitor the left overs and remove after a few minutes if not eaten.

he does water changes regularly removing 30 gals at a time...i dont have the specs on water parameters yet but he is getting that info for me and should have it tomorrow...

any ideas on what is happening to the crabs?

thanks...
Mario

 

[Hara]

EEK! He needs to feed no more than every other day. do water changes and shut off all the lights and keep them off. What type of filtration does he have?

 

[Gordinho80]

filtration is a sump system with bioballs and other media...plenty of filtration...has a strong pump on there...

i've told him on numerous occasions to feed less...

 

[Sadielynn]

Question has he ever treated with copper

 

[Hara]

actually, bioballs are known to be nitrate factories. Inverts cannot tolerate high nitrates. Given the amount being fed and the type of filtration, I would suspect the nitrates are off the charts. Do some testing and bring us some real numbers and lets figure this out.

 

[melosu58]

I was going to say that inverts are very sensitive to nitrates. We have many indicators telling us that nitrates are the problem here. Feeding twice a day and seeing leftover food is one. The wet dry is another one as Lisa said they are nitrate factories.And the increase of algea in the tank is also the result of excessive nutrients in the tank. I agree that test results will be neccesary to verify this. Hope all works out.

 

[Gordinho80]

got the tests done...FINALLY...

Ammonia: 0
Nitrites: 0
pH: 7.8
Nitrates: 80

Nitrates seems a little high...what are optimal parameters for SW - Fish/Inverts only...

thanks...
Mario

 

[Hara]

zero is optimal..anything over 20 is creating alot of problems.

 

[melosu58]

I agree that over 20 is a problem.

 

[roka64]

I difinitely agree 80 way too high.

 

[Gordinho80]

what is the best way to get Nitrates down in a SW setup?

 

[melosu58]

Weekly 20-25 % PWC`s

 

[roka64]

Weekly 20-25 % PWC`s

Also, feed everyother day.

 

[Gordinho80]

ok...updating on this...the crabs were not dying, in fact, they were only changing shells...they are all fine...every fish is fine...

feeding has been cut down to half and PWCs have been done every week in order to lower the Nitrates...all fish and inverts appear to be doing great...

thanks all for the support...

 

[roka64]

Great! I didn't even think to mention that they molt! I would stay on top of those nitrAtes and all should be good.

 

[austinsdad]

Any chance of talking him into live rock. W/out using any and bio-balls, I think he's in a never ending cycle. Water change, nitrates down, then back up again.

Still confused thugh. I believe your orignal post says both - he has no rocks and algae is on the rocks.

Also, some (including me) feed every other day.

Also, 3 crabs in a 6 month old 120g tank. Need about 100 more IMO to eat that leftover food. Snails, starfish, shrimp etc, are your basic cleaning crew that may help too IMO.

 

[Gordinho80]

sorry...no Live Rock...he has rock for decor...not Live Rock...he wants live rock and is probably getting 50-100lbs of it soon...

so if he gets Live Rock, he doesnt need the bio balls?

 

[roka64]

Yeah, if you go with 1.5-2Lbs of rock per gallon, you really don't need a filter. I use my filter for a little extra water movement and to run carbon, if needed. We were saying you can break up some of the LRR, into rubble and replace the bio balls with that.

 

[austinsdad]

Need more cleaning crew too.