Back from Vacation...Green Water! - Aquarium Algae Control & Specific Problems

DJKronik57 · 08-13-2006, 09:34 PM

I just got back from a week away from my tanks and one (20 Gallon) has developed a really bad case of green water. It's a relatively new tank which is probably why it happened (only about a month old in its current form). I only missed one dosing of ferts and was a day late on my water change. What can I do to get rid of it? I can't even see if everything is okay in it! Should I try a black out? Keep fertilizing? Lots of water changes?

Currently dosing 3x a week:

1/8 tsp CSM+B
1/4 tsp KNO3
1/4 tsp K2SO4
1/16 tsp KH2PO4

Lighting is 104W for 10-11 hours a day.
CO2 is two DIY yeast bottles.

There are 6 rummynose tetras, 2 ottos, and 2 amanos in there right now. As for plants, a carpet of HC is all.

MatPat · 08-14-2006, 12:47 PM

A 3 day blackout should cure the problem as would a diatom filter, but he blackout is free. Either of those will take car of the issue now but you must figure out what caused it in the first place to keep it from coming back.

Since it is a new tank I would guess the GW came from a NH4 (ammonium) spike in the tank while you were gone. The higeher levels of NH4 may have been caused by a decrease in CO2 levels while you were away making the plants slow their uptake of NH4.

Do a waterchange and add your ferts before the blackout. You can do another WC after the blackout if it makes you feel better but I don't think it is needed. Let us know how it works out for you.

hoppycalif · 08-14-2006, 03:40 PM

You do have a high light intensity too, more than 5 watts per gallon, and you leave the light on for a long time. To make things a lot easier on yourself at least cut the lights on time down to 8 hours. Things can get out of control very quickly with that much light.

DJKronik57 · 08-14-2006, 04:04 PM

Will the HC do alright with a shorter light period or intensity? I have one bank off now, so it's only 52W or 2.6wpg. I'm just worried about killing off my HC.

hoppycalif · 08-14-2006, 05:26 PM

2.6 watts per gallon is adequate light for a 20 gallon tank, so I don't think the HC will stop growing. It will probably just grow higher in trying to reach for the light. Everything I have read says those plants that signal that they have had enough light for the day, by folding their leaves, for example, do that after about 8 hours. That convinced me that 8 hours is enough, and thats all I do now, with no growth problems.

MatPat · 08-14-2006, 05:34 PM

I to have noticed the majority of stem plants close up their leaves in the range of 8-10 hours. By lowering my photoperiod to 8 hours I have eliminated or at least reduced the amount of algae in my tanks. Plants have not seemed to suffer from the light reduction either.

DJKronik57 · 08-17-2006, 09:00 PM

Well I'm trying a natural approach. I put in a breeder net with a whole bunch of daphnia and turned off one bank of lights and shortened the light period. Most of my stem plants close up after 12 hours, so that's why I had it set for 12. I'll let you all know how it goes...I might be resorting to a blackout.

DJKronik57 · 08-22-2006, 05:45 PM

Well, no luck with the daphnia. I popped a few in a jar filled with green water and they've cleaned that up nicely, but the tank continues to be pea soup. So I'm resorting to a black out. I will let you know how that works out in 3 days.

It seems green water is somewhat "contagious" as well, since my 29 gallon has started to get cloudy. I'm going to be posting another topic on this and why I think algae may not be omnipresent but instead pathogenic. My question is, what do I do? Cut lights or leave lights? Stop fertilizing or continue fertilizing? I've gotten advice both ways, so I'm unsure of what to do, besides black out the tank!

If I cut the lights or light period, the plants will photosynthesize less, using less nutrients, thus freeing up more nutrients for the GW which can withstand lower lights better than plants (unless there were always excess nutrients, in which case cutting back would further exacerbate the problem). If I stop fertilizing, the same is true, plants will use up all the nutrients they can then stop, leaving some excess nutrients for the GW once they run out of another.

Following this logic, I should do nothing! Yet that clearly isn't working. If GW is pathogenic, then really I can't do anything but a black out.

I've heard GW may be caused by NH4 spikes, so what if I just stop or cut back on my KNO3 to force the plants to use up all the nitrates and ammonia? I'm grasping at threads here as I watch my tanks fade into oblivion! Anyone?

redstrat · 08-22-2006, 06:26 PM

GW is a mysterious problem... I beleive its truely caused by an ammonia spike then once its there its very tough to get rid of. I have tried so many things short of spending a ton of money on a UV sterilizer or a Diatom Filter. I have even tried cutting nitrogen to force a little defficiency, the GW cleared in a couple days the first time I tried it but then came back as soon as I added any Nitrogen. After the months I spent trying to get a grip on the GW problem in my tank I found that as long as CO2 is kept at high concentrations, nutrients are balanced (this takes time to figure out but try going lean answering any defficiencies then build it up, if EI fails you first like it did for me). Then once you get all these things in check, set your lighting to an 8-10 hour photoperiod (be sure you dont get a lot of light from nearby windows or other stray light sources), this seemed to have the most dramatic effect on my GW problem. I have been GW free for several weeks now after a several month long bout with it. I think its safe to say I have overcome it with purchasing anything expensive or really spending any additional money. The best weapons for GW are control and balance. By the way I have been able to dose approximately 3 times as much ferts now that I'm on a 9 hour photoperiod, its as if the plants start to slow nutrient uptake to a crawl after that much exposure and this is when GW gets its chance to strike, at least in my case. My plants are also growing much faster and better on the shorter photoperiod. The general rule I have found proven true more often then not is that more light is generally a good thing, but longer photoperiods are not.
I hope this helps.

Good luck

DJKronik57 · 08-22-2006, 07:26 PM

Quote:

By the way I have been able to dose approximately 3 times as much ferts now that I'm on a 9 hour photoperiod, its as if the plants start to slow nutrient uptake to a crawl after that much exposure and this is when GW gets its chance to strike, at least in my case. My plants are also growing much faster and better on the shorter photoperiod.

Hmm...that's very interesting. Can anyone else support this? If plants do "turn off" after a certain number of hours that would make sense, it's just hard to figure out why you would be able to dose 3x more and the plants would be growing better with a shorter photo period. Maybe a longer photoperiod gives them less time to recover and grow when the lights are off? Don't plants actually do most of their growing when lights are off?