Algae in water

[Tammy]

After two months of changing the water every week 30%. After 34 days the water gets a little greener and greener each day I have had a little algae on the side of the tank once but mostly it seems like it’s just in the water I’ve discussed this once before and I don’t know what to do at this point I have a hang on the back filter do I need to add a sponge filter. It is a 15 gallon planted tank. It does not get the same amount of light every day at the same time. It is my granddaughter’s tank and I’m trying to care for it for them. Their mother does not want to put it on a timer because someone they know had their tank light cord melt and start smoking and it ruined the whole room and had to be repainted. So I can’t put the light on a timer. There is not light coming in from the window shining on the tank either.I still do not know if it’s green algae in the water but I believe it is, that being said do I need to cover paper around the entire tank to make it completely dark for one full week. I have about six plants in the tank that are doing well

[Tammy]

Algae in water. I just left a message and I put 34 days it’s 3 to 4 days I start seeing Algae in the water

[Mmiller2001]

You can do a blackout for 3 days or get a UV sterilizer. The sterilizer works really well and quickly.

And I would drop the light intensity just a bit going forward.

Edited June 21, 2022 by Mmiller2001

[Kurt Brutting]

How long is the light on for maybe drop the duration? 

[a.modest.aquarist]

Have you recently checked your ammonia levels? Elevated ammonia levels combined with too much light is a common cause for this. Although you're doing regular water changes I would also check your filter to see if it needs to be cleaned and see if your substrate need to be vacuumed. If your ammonia levels are good, than the most likely the duration/intensity of your light is the culprit. In addition to the suggested black out, a 5 hour photo-period for a couple weeks also works well.

[Tammy]

How do I do the last sentence you’re talking about the five hour blackout  Photo – period , what does that mean?

[a.modest.aquarist]

The blackout method mentioned by Mmiller2001 is simply leaving the light off and covering all sides and top of the tank to block out all light; this includes ambient lighting. People often use cardboard boxes/paper, large trash bag pulled over the tank, etc. Photo-period is referring to how long you leave your aquarium light on for. So the suggestions are either a three day blackout, leaving the light on for 5 hours max per day for a couple weeks, or a combination of both. eg. blackout > 5 hours/day. Without a timer its a bit cumbersome, but sticking to a more consistent lighting period will help with the green water algae and prevent other algae issues in the future.

[Tammy]

That was very helpful. Thank you so so much