Help with SW tank

[divadro102]

Hi guys. Have a couple questions. But a little info first (sorry if it's long, i like to state exactly what i need to) :::

My dad and I have a 90g tank that used to be FW and housed a huge pleco. Sadly he died and my dad wanted SW fish, so we started that cycle and went out to sea and had us a few caught wild ones. That was over 6 years ago and the tank lasted a year until my dad got tired of cleaning it up. No fish ever died. The tank stood empty for the past 5 years until 6 months ago. We decided to set it up again. We let the tank sit, cycle, and get it's bacteria and had proper levels before placing new SW fish.

We're kinda poor so we have the canister filter from when it used to be FW. Also, the water we use is straight from the tap without RO. Risky but no fish has ever died and it's obviously dechlorinated, etc...

Ok, so the new tank has been good. This tank is new for us in the sense that we actually bought the fish and live rock. All levels have been great.

Now my questions:

We had to cycle our tank after it was set with damselfish. Our LFS asked us to return them after the tank finished its cycle but we fell in love with them and kept them. After three months, we decided to buy new fish. So we got compatible ones and they died after biting on the live rock. We bought new ones again and they died after chewing on the rock. After a fourth buy we noticed that the new fish, except the damsels, chew on the rock and die within two days with swollen mouths. What could that be? Each single fish that dies, has chewed the rock and died from the exact same thing. A swollen-open mouth, tries to eat but can't close the lips, and then sinks to the bottom.

And just last week, my dad bought water for the first time from the LFS to change out 20 gallons. The water cleared up and looked nice the first two days. Then our 19 fish became 7 in a matter of days. We think the culprit may be the new water from the LFS but the only ones to die are the striped and spotted damsels. The yellowfins haven't been plucked out of the water yet.

EDIT: Also, i'm aware that the canister is pretty much freshwater technology. But the SW fish from 6 years back were fine for a year and these new ones have done great so far. The tank used to house 80 tetras, two bettas, and two plecos. One died, the other grew really big.

 

[huma-huma]

Canister filters are by no means fw tech...there are very common on sw tanks. Idk what the issue is with the rocks but 17 damsels in a 90 seems a bit much. Also we need as many specifics about your setup as possible so we can help solve issues. For example lbs of live rock and sand, powerheads, what type of filter, feeding schedule, and the such. Like I said as many specifics as possible

 

[divadro102]

The filter is a Magnum 350 Pro. It uses carbon filtration. I figured they were mostly for FW because of all the shops i've been to have told me about a proper setup and some of our family friends have "proper" setups. Then again, their garage houses the water tanks.

There are no powerheads?? Not sure what that is. The filter has an in/out on the side and two bio-wheels up top that create a current.

We have about 20-26 lbs of crushed coral as substrate. It forms an inch from the bottom up. We have a single 10 pound live rock. No coral reefs. There's a SW safe "broken" vase, pieces of dead coral but not crushed, and a medium conch. It's a SW tank with live rock and fish.

We actually had 20 damsels. 6 three spotted, 6 four striped, and 8 yellowtails. And also 4 hermit crabs that were clung to the rock when we bought it. 20 does seem a bit much, but the fish are small and barely took up space. Obviously ammonia is a factor, but it was controlled.

The lights are on at 11 or 12am, and get turned off after 6-8 hours. It controls the algae. And we feed them flakes every other day. Sometimes we give them live food and frozen shrimp, but these make a mess no matter how small and the damsels weren't too fond of them.

Right now there are two striped damsels, 1 spotted, and 6 yellowtailed damsels. The rest died. Newer fish of the same type were doing ok for the past month. We bought two blue damsels that were all blue and were the first i noticed to chew on the rock. None of our other damsels chew on it. Then these two died with swollen mouths. When we bought three foxface, we noticed they immediately went straight to the rock and started chewing on it. One was dead the next morning with that swollen mouth. The other died next day without any symptoms, just instant death. And the third lasted a week before its mouth swelled and died.

We wanted newer, expensive fish to add but after those three foxface died, we decided to change the water with water from our LFS because they recommended we do that.

Well last week we did and that's all that happened. All our healthy "old" fish are now dying of the same thing. A reddish algae has formed on the filter basket, conch, and dead corals. A yellowish algae has formed on the top of the substrate and only in the areas where light hits.

I'm not sure what else to say. The feeding is the same, hours for lighting, and clean up is all the same. No change except water. We always test weekly and nitrates/nitrites are not at 0. They're low not high. And ammonia has always been very low but never at 0. No chlorine, 1.024 of salinity, ph fluctuates from 6.5 to 7.9, carbonate hardness is around 120.

 

[huma-huma]

Please don't take this negatively, just giving you my opinion and trying to help out you have a 90g tank that did at one point have 20 fish and the only filtration you had was a 10 lb live rock and an aged canister. General rule of thumb is 1-2 lbs of live rock for every gallon. Fish-only tanks are exceptions but have to have heavy duty mechanical filtration. I notices that you said ammonia/trites/trates are low but not 0.. a properly cycled tank will show 0/0/0<... if you are showing ANY signs of ammonia and or trites then you either don't have a properly cycled tank or your bioload is overwhelming your filtration. If the 10 lb rock is the supposed issue, go buy some new rock,let it sit in tank for 2 weeks, then pitch the old rock..... so all in all id say you need to either buy alot more rock or bulk up your filtration.

 

[huma-huma]

Please don't take this negatively, just giving you my opinion and trying to help out you have a 90g tank that did at one point have 20 fish and the only filtration you had was a 10 lb live rock and an aged canister. General rule of thumb is 1-2 lbs of live rock for every gallon. Fish-only tanks are exceptions but have to have heavy duty mechanical filtration. I notices that you said ammonia/trites/trates are low but not 0.. a properly cycled tank will show 0/0/0<... if you are showing ANY signs of ammonia and or trites then you either don't have a properly cycled tank or your bioload is overwhelming your filtration. If the 10 lb rock is the supposed issue, go buy some new rock,let it sit in tank for 2 weeks, then pitch the old rock..... so all in all id say you need to either buy alot more rock or bulk up your filtration.

**edit** your ph shouldn't be that low on sw tank. 7.5 is low....6.5 is bad... how did you cycle the tank and when/how did you know it was cycled

 

[divadro102]

**edit** your ph shouldn't be that low on sw tank. 7.5 is low....6.5 is bad... how did you cycle the tank and when/how did you know it was cycled

The canister filter is a brand new one from when the tank was in use years back, we just never actually opened it up and decided to tear down the tank. 6 months back, after 5 years, we decided to do it again how it was but instead of wild fish and the old filter, we used the new one and bought our fish this time.

The tank sat alone with water from our tap, two weeks, since we don't have/use RO and the carbon from the filter cleared it up a bit. Then the guy at the LFS said with one rock and 6 damsels it would be ok so that the tank has bacteria and can cycle assuming the levels are ok before placing the fish. Everything was good and the 10lb rock, and 6 damsels were placed. Then we kept the tank the same for two months before buying new fish or returning the damsels. The LFS told us that nitrate/nitrite shouldn't be at 0 when it's cycled. Rather, it should be low but not high. It has. He told us that the PH should also be kept between 7.5 and 8.5. He said it's not a reef tank, so it doesn't need to be that high. So it's mostly around 7.8. I mentioned 6.5 because it dropped twice these past 6 months and it might be important to add.

I'm also aware of the lbs of rock per gallon, and he was going to sell us 60 pounds of rock. This one 10 pounder was already 71 bucks. We're definitely too broke for more and it's my dad's tank. He doesn't want more rock. I tell him it's good for it, blah blah. But it all falls ondeaf ears because the fish have been fine and so have the new ones up until the water from the LFS.

I would put more monetary effort into the tank, but the foxface i bought were 40 bucks total and they died within a week. Anything that's not a damsel has died, except for the two that happened to chew on rock. Besides, i have my own FW tank that's still going strong after i took the tank out of storage 9 months back.

I'm sorry if i write so much and sound repetitive but really, it's this bit that gets at me: Each new fish that chews on that d*mn rock dies the next day or within the week.

The fish that are dying now never chew on the rock and came after the water change. So i think, i'll take out the rock and let it die, buy some new ones, see if any more fish die and do water changes.

 

[huma-huma]

Yeah unfortunately without either alot more rock or a beefier mechanical filtration, prob not gonna have luck. In terms of your lfs telling you the trites/trates shouldn't be at zero, they are partially wrong... a truly completely cycled tank should show 0ammo-0trites- and 5-20ish trates. I personally would suggest to start over from square one and cycle it again. Only this time buy a master test kit (api or safialert) and test 2 times a day until the you've clearly verified the cycle is fully finished. IMO there's just too much going on to effectively straighten it out. By no means saying you're doing anything wrong but it seems you were given bad info

 

[divadro102]

Yeah unfortunately without either alot more rock or a beefier mechanical filtration, prob not gonna have luck. In terms of your lfs telling you the trites/trates shouldn't be at zero, they are partially wrong... a truly completely cycled tank should show 0ammo-0trites- and 5-20ish trates. I personally would suggest to start over from square one and cycle it again. Only this time buy a master test kit (api or safialert) and test 2 times a day until the you've clearly verified the cycle is fully finished. IMO there's just too much going on to effectively straighten it out. By no means saying you're doing anything wrong but it seems you were given bad info

I agree with the bad info from my LFS, but the tank has been well even if the levels weren't necessarily perfect. Maybe the tank wasn't cycled properly, but still, 6 months of healthy fish kind of defeats all else. To reiterate, two batches of foxface died after chewing the rock, and 3 months later, most of the healthy fish die after buying water from my LFS.

I do have the API master kit. I recently checked again, all levels are at zero, except ammonia, it's at .25 ., The ph is 8.2, is that ok? What's the ideal ph for a saltwater tank. And what would be the proper way of cycling the tank from zero. I feel that it's best to just start over. Thank you for the responses

 

[crister13]

8.2 is good but in a cycled tank ammo and trites should be 0