Green water and CO2

"Shawn" wrote in message
...

I'm not a chemist. Can someone tell me what KNO3 is and where I can buy
it

KNO3 is pottassium Nitrate. You should be able to buy it at a hydroponic
supplier.

Are you sure you need it?

Graham.

No - I'm not sure I need it ! I don't know what the h*ll I need anymore !
My green water algae outbreak is driving me bonkers. I saw a post a few
days ago from someone saying to dose with 1 tsp KN03 every other day to get
rid of it.

I see so many opinions, everything from total darkness blackout to total
takedown of aquarium with chlorine disinfection, dip all plants and start
over again to barley straw extra to uv sterilization.

The only only I've tried at this point is the total blackout. I wrapped my
55gal tank in a thick comforter, duct taped it down so NO light was getting
in, and left it that way for 5 full days. My poor fish ! I took if off on
day 5 and voila ! Crystal clear water ! I thought I had it beat. My fish
looked OK. My higher plants still looked healthy. But about 4 days later,
the water starts looking a little green, 2 more days later more green, now
it's pea soup again.

My tank used to be such a joy. It's been running for 5 years with no
problems whatsoever like this. No I can't even stand to look at it. It's
ugly. Diatom filters seem expensive and problematic what with all the
changing of active ingredients etc etc. I don't want to take it all down
and disinfect. Besides, I have to put the fish somewhere, and even if I
stuck them all in a 10-gal for the day with fresh water, just the small
amount of water on my net or on the fish could contain green water algae
cells which would then go right back into my big tank and start everything
all over again.

I don't know what to do. Do you have any advice ?

Shawn



"Graham Broadbridge" wrote in message
...
"Shawn" wrote in message
...

I'm not a chemist. Can someone tell me what KNO3 is and where I can buy
it

KNO3 is pottassium Nitrate. You should be able to buy it at a hydroponic
supplier.

Are you sure you need it?

Graham.

"Shawn" wrote in message
...
No - I'm not sure I need it ! I don't know what the h*ll I need anymore !
My green water algae outbreak is driving me bonkers. I saw a post a few
days ago from someone saying to dose with 1 tsp KN03 every other day to
get
rid of it.

Okay, first of all, do some tests (or get your LFS to test for you).

The important numbers are nitrates, iron and phosphate.

Nitrates should be under 20ppm, iron under 0.1 ppm, and phosphate as close
to zero as possible. Assuming one or more is higher, you need to reduce
them.

Reduce nitrate and phosphate by daily water changes of 10-15% I don't
expect that your iron will be too high but if it is, water changes will fix
that too. It may take a while for the water changes to reduce levels
significantly, especially if they're high to start with.

Once the water chemistry is right, the green cloud will dissapate itself
after a week or so. If not you could use a floculant to cause it to drop to
the tank bottom and vacuum it out.

Graham.