The damage of a 100% water change with a canister filter

[jcarr71]

I am cracking with this water problem. Green water, microscopic algae. I've been doing two oversized water changes a week and within days the water is green again. No ammonia, no nitrites. Nitrates are under 20 ppm. The filtration is mainly a Rena XP3, though there is also an aqualclear 50 tacked on mainly for surface agitation. My lighting is HALF of what was recommended to me in terms of watts to grow plants here because I was poor. They run eight hours a day, 1-9 pm, on a timer.

Yet, I cannot clear this water. The 10g and 29g running on the same exact timer are 100000000000000x clearer. The 10g is as clear as air. I have tried algae killers from Wal-Mart. I tried just waiting it out once. I blocked off the side of the tank near a window weeks ago.

STILL GREEN WATER!

...

help


I'm so annoyed I want to do a 100% water change. I want to shut the filters off, put all the fish in buckets, and replace ALL the water except for what is in the Rena canister filter. How much damage would this do? It would take a few hours, but the bacteria in the Rena wouldn't die, so the tank wouldn't completely uncycle.

Tell me this is an awful idea before I do it.

[Lady Hobbs]

You can do a large water change easily. I do 50% on all my tanks every week.

However, your tank can catch no direct sunlight or you'll have green water. If it's near sunlight, the tank will have to be moved or the window shaded.

I did about a 95% yesterday when re-doing a tank. The bacteria is in your filter, not in the water.

[smaug]

It could be phosphates.I do know the only way to kill it completly sometimes is a week long complete black out of the tank.Its not happening for no reason,there is something in there causing it.The lower lighting could actually be harming,I know thats contradictory to having a black out but hear me out.If your plants are not getting the correct light then they are absorbing very little nutrients which is allowing the gw to have more.I dont recomend putting more light on it right now but when you get it cleared up it could help.What type lighting and what k rating do you have now?

[Northernguy]

Have you cleaned out the Rena lately?
Are your hoses clear of algae!
I have my tank set up in front of some French doors.
They let in a very large amount of sunlight.My filter and hoses would turn green with algae.
I put white bristol board on the back of my tank to reflect the sun and I covered my hoses with those Black foam copper pipe insulators.
It has made a huge difference.
I have no more algae issues in that tank!

[Mith]

I got a question... is there ever a case where green water is NOT related to too much light?

[Northernguy]

Water coloring!
Other than that its all algae and light.
As far as I know! :14:

[jaysee]

I have a tank that catches some diect light. I put a UV in it and haven't had any algae since.

[sheamurai]

If you don't have enough light to properly grow plants, then I would yank them. I had that same problem with my 16gal - I did water changes every other day, and still the green. Then someone mentioned that poor lighting (with plants) is as bad as too much lighting for algae. I pulled out the plants and did a water change, and that was the end of my green water problem.

[jaysee]

Are you using fertilizers?

[Jaster]

I have a tank that gets a good amount of actual sunlight and algae is a constant fight. I borrowed a friends UV sterilizer just to see what it would do and within a week (8 hours a day) of putting it in there my water was clear. So one is now on my wishlist. If nothing else you are doing is working I would say get the UV.

[KingFisher]

Try filling that AC50 with purigen or Chemi-pure. They will absorb the excess nutrients from the water and the algae won't have any food to grow.

[BigMac]

I used a phosphate absorbing materiel and my green hair algea went completely nuts... I ended up re plating the tank.
I raised my phosphate level to match my NO3 at about a 10-1 ratio and all the algea died off and my plants went flat nuts.

[KingFisher]

I used a phosphate absorbing materiel and my green hair algea went completely nuts... I ended up re plating the tank.
I raised my phosphate level to match my NO3 at about a 10-1 ratio and all the algea died off and my plants went flat nuts.


You have a co2 injected tank with sufficient lighting. The OP's tank is much different, therefore a different approach is needed.

[sheamurai]

Hmm, I don't believe that Purigen is much of an algae deterrent. I have two pouches of it in my canister filter on the 77gal, and still have algae growing - just enough to keep my otos happy!

[bushwhacker]

jcarr i posted this in a thread in newbies but its something you may want to try.

i cant vouch for this personaly, but google search for willow branches and green water. it's said to work great, but you cant leave them in all the times as it will take all the nutrients out of your tank and starve your plants along with the green algae

[bushwhacker]

not the same artical but this explains it

Green Water

Description This is a unicellular algae. Water goes cloudy. Sometimes just a green tint, other times it can look like pea soup.
Cause Ammonia is often the main cause green water. There may have been an ammonia spike that isn't detected with test kits. Other possible causes are an imbalance of nutrients and/or low CO2 levels.
Removal Large water changes do not seem to always help. If there is an imbalance in nutrients then fixing it will sometimes make it go away by itself after a while. A three day blackout followed by a large water change will hit it hard and sometimes may clear it. A UV steriliser/clarifier or diatom filter will clear it up very quickly and is often the only way to clear it.
A new method is to use freshly cut 1-2 year old willow branches about 0.5-1cm in width. Place these in your tank vertically so they go from the substrate to a few centimetres above the water's surface. After a few days they will start to grow roots and the green water should start to clear. When cleared remove the branches from the water.
Don't confuse this with a bacterial bloom which gives the water a white haze.

[Discus_Dude]

There are many variables such as natural light, the type of tank lights you use, the length of time you leave your lights on, if planted what fertilizers you use, natural phosophates from your water source, some PH buffers if used, some foods, just to name a few.

You need to consider all. Increase the amount of your water changes, phosophates could easily be removed with added media for just for this purpose, a UV light as you know. There are other options, but they can be more expensive.

Best of luck!

[i_am_511]

This is another choice you have.... You could get a clam from your LFS or have them order a few for you. They shouldnt be nothing but a few bucks maybe a little more and they would eat(filter feeders) the green out the water REALLY fast. Ive heard of people making green water and pouring it in the tank to feed there clams.

[blue fin]

I fought green water for three months after inheriting my tank from my step-father who had placed the tank in bright sunlight for 3 months. NO sun, dim illumination in the room, frequent water changes.. sometimes three in a week.... all to no avail. The UV light did the trick for me. I found one online for 50 dollars that had it's own pump, just installed it in the tank and ran it for a couple of months. There was a noticeable change in the tank after only a few days and after a week the water was beautifully clear. I left it running for a couple months more just to be sure. I disconnected at that point and have not had a problem since.

[jcarr71]

I ended up taping cardboard over the side that gets sunlight and doing a massive water change. The water isn't crystal clear like it used to be, but it also isn't changing into pea soup like it had been either. In fact, I'd say it is a tiny bit clearer every day. I think I am winning!

Thanks for the help everyone.