UV Sterlizers, algae blooms, cloudy water...

[Rex]

Hello!

New here, been browsing for a while and decided to join now as my girl and I want to join and attend the next meeting =)
Anyways, I've have a 20 gallon planted tank for over a year and it's had a bit of history. When I first got it, I knew about lighting and fertilization/c02 but not much about water chemistry. It was alright for a while but got a terrible outbreak of what I think was staghorn algae, really coarse, dark hair like stuff. I tried many different things to no avail, and after we moved back to Ottawa from Renfrew, I broke down the tank and started it over with new gravel and new plants.

All was well, it got cloudy for a short while as the nitrifying bacteria lost through the gravel change multiplied again, though once that was through, I had an outbreak of green water which has lasted for the past two months.

I've researched and done everything I could from feeding less, keeping lights on less, testing all the water parameters and understanding them...but there is no ammonia, no nitrates, no phosphates present at all. I took home tests and even brought the water into Big Al's for testing to confirm that. I do weekly water changes of about 25-50%, my PH is 6.8-7.0. It's c02 injected and my GH and KH are very low, 2.2 dH or 40 ppm, although I don't know anything about very soft water other than it means my pH should be around 6.6 for optimal c02 levels. My only guess is there's too much ambient light which could be causing the blooms. I've tried chemical treatment (Nutrafin Pclear with polywool in the filter) which cleared it up fantastically, but it keeps coming back. I would try a blackout, but it seems obvious it would just come back again as I already managed to get it clear before.

Now for my questions. I've read about UV sterilizers and they seem like a great option for treating green water and general water quality. I have my eye on the Coralife Turbo Twist 3X 9 watt model, but it says it's rated for tanks up to 125 gallons and I'm worried it could be overkill/harmful for a 20 gallon. I use a Rena XP1 canister filter rated at 250 gph so hookup should be no problem (as long as the sterilizer takes the giant tubing that the filter uses).
I did see 5 watt model at Big Al's Online (http://www.bigalsonline.ca/BigAlsCA/ctl3664/cp18126/si1317441/cl0/aquamedicuvsterilizer5watt), but it seems it may be too small to be placed in the outlet of the XP1. Plus, I plan to upgrade to a 40 gallon tank in the near future when space permits anyway.
So what would you think my best option is? If the Coralife is overkill, would hooking it up to a timer make it a plausible option?

Wow, I didn't mean to make this post so long. Thanks for reading it all...heh.

[BigDaddy]

Green water almost always occurs when there are even trace amounts of ammonia in the water.  Given your "mini cycle" it sounds like you fit the bill.  Even if your ammonia reads zero, trace amounts can and will trigger green water.

The black out will work great if you think your system is now cycled.  Once green water takes it will hold on after the trigger is long gone.  However, if you still might be suffering from a small cycle (i.e. it has been less than around 6 weeks since you had measurable nitrite or ammonia) you may want to consider a UV or diatom filter as preventive maintenance.

Why not try the free option first and then barring that buy a diatom filter or UV sterilizer?  HOT Magnums make great cheap diatom filters and have a usable life afterwards as a water polisher and a backup filter without breaking the bank.

[charlie]

Green water almost always occurs when there are even trace amounts of ammonia in the water.  Given your "mini cycle" it sounds like you fit the bill.  Even if your ammonia reads zero, trace amounts can and will trigger green water.The black out will work great if you think your system is now cycled.  Once green water takes it will hold on after the trigger is long gone.  However, if you still might be suffering from a small cycle (i.e. it has been less than around 6 weeks since you had measurable nitrite or ammonia) you may want to consider a UV or diatom filter as preventive maintenance.Why not try the free option first and then barring that buy a diatom filter or UV sterilizer?  HOT Magnums make great cheap diatom filters and have a usable life afterwards as a water polisher and a backup filter without breaking the bank.

I have to agree,a black out is the way to go before going to UV.

Hello!

New here, been browsing for a while and decided to join now as my girl and I want to join and attend the next meeting =)
Anyways, I've have a 20 gallon planted tank for over a year and it's had a bit of history. When I first got it, I knew about lighting and fertilization/c02 but not much about water chemistry. It was alright for a while but got a terrible outbreak of what I think was staghorn algae, really coarse, dark hair like stuff. I tried many different things to no avail, and after we moved back to Ottawa from Renfrew, I broke down the tank and started it over with new gravel and new plants.

All was well, it got cloudy for a short while as the nitrifying bacteria lost through the gravel change multiplied again, though once that was through, I had an outbreak of green water which has lasted for the past two months.

I've researched and done everything I could from feeding less, keeping lights on less, testing all the water parameters and understanding them...but there is no ammonia, no nitrates, no phosphates present at all. I took home tests and even brought the water into Big Al's for testing to confirm that. I do weekly water changes of about 25-50%, my PH is 6.8-7.0. It's c02 injected and my GH and KH are very low, 2.2 dH or 40 ppm, although I don't know anything about very soft water other than it means my pH should be around 6.6 for optimal c02 levels. My only guess is there's too much ambient light which could be causing the blooms. I've tried chemical treatment (Nutrafin Pclear with polywool in the filter) which cleared it up fantastically, but it keeps coming back. I would try a blackout, but it seems obvious it would just come back again as I already managed to get it clear before.

Now for my questions. I've read about UV sterilizers and they seem like a great option for treating green water and general water quality. I have my eye on the Coralife Turbo Twist 3X 9 watt model, but it says it's rated for tanks up to 125 gallons and I'm worried it could be overkill/harmful for a 20 gallon. I use a Rena XP1 canister filter rated at 250 gph so hookup should be no problem (as long as the sterilizer takes the giant tubing that the filter uses).
I did see 5 watt model at Big Al's Online (http://www.bigalsonline.ca/BigAlsCA/ctl3664/cp18126/si1317441/cl0/aquamedicuvsterilizer5watt), but it seems it may be too small to be placed in the outlet of the XP1. Plus, I plan to upgrade to a 40 gallon tank in the near future when space permits anyway.
So what would you think my best option is? If the Coralife is overkill, would hooking it up to a timer make it a plausible option?

Wow, I didn't mean to make this post so long. Thanks for reading it all...heh.

What is your present bio load ? What type of lighting & how many watts on that 20 gln ?
Here is something that concerns me , you say you have no Nitrates & Phosphates, that means one of 2 things your test kits are not reading accurate or your plants are super hungry & is depleting  all Nitartes & Phosphates, despite what some folks think , in a planted tank you need to have Nitrate & Phosphates  for the plant more so when you are injecting CO2 & high lights.No Nitrates & Phosphates will lead to stunted growth & algae bloom.
Regards

[dan2x38]

Hey the advice your getting from Charlie & BigDaddy is from 2 of the the best. You say no nitrate (NO3) that points to a mini cycle there should be NO3 present. Go for the Black-out first much cheaper start.

[Rex]

Thanks for the advice so far, I will try a blackout. Though as I mentioned, I already got the water crystal clear earlier this week through chemical treatment - and the green water is coming back. Is there something in using the blackout method that helps prevent further algae blooms?

Oh yeah, about the bioload, I'm thinking it may be under-stocked? I have 4 small cory's, 5 platies, 2 mollies and 2 surviving neons.