whats happening in the tank???

Ding Dong

Hi, I recently bought a Fluval 190 tank with a Fluval 205 filter. I filled it with water from the outdoor tap (maybe first mistake as the water prob has nutrients etc and isnt filtered). Within a week the tank developed a green hue in the water. N.B. its not in direct sunlight and theres no overfeeding. Anyway, gave the tank a dose of ‘greenaway’, with not much luck. Did a qtr change which helped a bit, but green hue came back quickly. Gave another dose of the ‘greenaway’, and left the tank covered in towels to block light for 3 days, but no improvement (see attached). Im moving the fish back into their original home at weekend as I bought this tank for a small number of larger fish.
So then I can really get to tackle the problem while the tank is empty but the questions for me are
Whats happening in the tank and how can I get rid of the problem?? (haven’t got a water testing kit yet – hope to later in week), I really want the problem resolved before I set the tank up for new fish. Any help please….

fred funk }{

I'd be more concerned about nitrites and ammonia because if you filled the tank directly from the tap, the chlorine in tap water will kill all the bacteria that's needed to have an effective nitrogen cycle.

Algae is nearly always harmless albeit unpleasant on the eye so you need to get an ammonia and nitrite test kits ASAP, their readings should be 0 in a cycled tank.

Have a read of the sticky at the top of the forum regarding cycling an aquarium.

Good luck.

Ding Dong

thanks for that. I presume my tank is not at zero. is there anything i can do ie by adding treatments so the tank is 'clean' before I begin cycling from the start again?

fred funk }{

Plenty of water changes with treated water and cut the food back to a pinch every three days. It's very important to get the test kits, they'll show you the different stages of the cycling process.

First thing I would do is a 50% water change and try have the new water the same temperature as the tank water so shock the fish.

Cookie_Monster

Im moving the fish back into their original home at weekend

is this a mature tank they are going back to? If so take a filter sponge out and squeeze it into the larger tanks, it'll help speed up the cycle

Ding Dong

it is a mature tank actually. so just a squeeze of the old filetrs and hold off on the chemicals and see if that sorts the green hue??

Sleepy

50% water change making sure you treat the new water with de-chlorinator of some sort and then rinse your sponges from the old tank in the new one.

Ding Dong

to stop green blooms etc coming back would anyone recommend using API Nitra Zorb to keep nitrates down or what treatment would you recommend?

fred funk }{

Water changes will keep the nitrate levels down. I'd try stay clear of chemicals and the like, apart from anything else, they're an expensive.

Ding Dong

thanks Fred. its strange, i have two other tanks, 35l and 125l and both gin clear, never needed water changes in first few weeks etc. new filters etc. this external filter on the 190l tank is just confusing me. set it up the same way as the other two, let it sit for two weeks, everything good, then once the fish are introduced (just a half dozen small cichlids) it just goes wrong.

So how much water change needs to be done per day do u think and how long do you think i will have to do it? the nitrates are down to less than 10ppm. im just getting really frustrated at it as i can never seem to ghet clear water!!!

fred funk }{

Your nitrate reading isn't too bad. I don'tthink your water clarity is connected to your nitrates. Food can be a major factor in water clarity and some foods cloud the water more than others. Give it time and im sure it will clear up. Make sure to use filter floss in the filter too.

I would just change about 20% water per week. That is based on normal conditions, if you over feed and are over stocked you'll need to increase that further.