The Planted Tank Forum banner

Algae ONLY on the glass - Overdosage of CO2 or Lighting?

3471 Views 10 Replies 6 Participants Last post by  MsNemoShrimp
It is almost 2 weeks since I flooded my 12G tank after a few months of growing DHG immersed. Since then, dosing CO2 24/7 via paintball CO2. 1 bpm. The reason it's 24/7 CO2 is because it doesn't have a solenoid so it's always on at 1 bmp. Never had a problem doing this before.

There isn't a problem...yet, and I hope not, but I want to avoid any before it happens.

* The 36" Fugeray is on 10 hours a day total.
10AM - 1PM (3 hrs.)
3PM - 6PM (3 hrs.)
8PM - 12AM (4 hrs.)

* 6.75" above the water surface, as in, the exact distance between where the light emits and the surface of the water.

* This tank has PLENTY of flow.

* Have a few Nerite snails, Amano shrimps and a whole farm of Painted Fire Red Shrimps.

* DHG and Mini Pellia is growing extra well. The M. Pellia leaves are becoming bigger, broader, instead of narrow.

The thing that concerns me at this moment is just the algae on the glass. I had to scrape down the glass because there is a good amount of algae on it. Don't see anything on the plants, stones, etc. though, just on the glass.

Does that mean:

1.) I have more CO2 than the light can "use up"?
2.) Not enough CO2?
3.) Lower the light?
4.) Raise the light?

Based off the charts, my par rating sits around 75 = medium/high light?

1 - 11 of 11 Posts

· Registered
3,322 Posts
It sounds like green dust algae. Do you have any pics? The lighting seems a bit high as well. Any reason why you run three photo periods? You can try raising the light a few more inches to get less par at the bottom of the tank.

· Banned
5,927 Posts
Having a split photo period can help/w algae and people also do that for viewing before going to work and after coming home in the P.M.
If there is no viewing reason for the period from 10 P.M. till you can just run the afternoon 3-6 P.M. one till 8 P.M. for a total of 8 hrs.
Don't know if the extra for a solinoid is worth it but the CO2 is wasted while the light is not on.
2-3bps is commonly used and is the reason most have shut off valves and timers on them. So 1bpm won't choke any shrimp but more may actually speed up the plant growth and cut that algae. Then you wouldn't notice the reduction in hrs as far as plant growth is concerned. I would try cuttng those hrs first cause raising the bpm
to like 4bpm might not hurt the shrimp but more than that I think would and cause the need of that solinoid. Actually these are very low levels of CO2.

· Registered
1,000 Posts
Having a split time does not mean it helps with algae. It is a perceived notion and not proven.

I think you have a little much light for as long as you leave it on for. Cut to 6hrs per day and you should not see it at all. I can get the same thing on a few of my tanks, but it never shows if I keep the period under control.

· ღ Miss ShrimpTastic! ஐ...
2,605 Posts
Discussion Starter · #5 ·
Thanks for the info. This is my FTS as of right now.

Basically all the algae on the glass (front only) is easily taken off with a Mag Float. It isn't extra thick or anything. I looked up green dust algae and some pictures threw me off so don't think it is right. It is more fuzzy, but VERY easy scraped off and it doesn't get on anything other than just glass. As you can see my tank is 99% "algae free" so to speak :)

If I had to take a wild wild guess, if I left the algae alone, it would look like this after 3 months or so based on the look on the glass?

With that being said, I'll definitely try to cut down the photo period to 8 hours and see if it helps because raising the light anymore is definitely doable, but I am not fond of it because 8" off the rim means most of the light will penetrate the area surrounding the tank and I don't like the extra lighting unless I have to.

I'll try 4 hr. periods

11AM - 3PM & 8PM - 12AM

One thing I want to clear off the list is that the light SHOULDN'T be any lower right? It's not like there is too much CO2 and the light doesn't burn off enough of it which triggers that glass algae?

· Registered
3,350 Posts
It's not like there is too much CO2 and the light doesn't burn off enough of it which triggers that glass algae?
Nope. While I've had high CO2 make a few algae worse, the types that grow on glass aren't included.

Light sounds like the prime candidate here, and the reduction in photoperiod you've already planned will probably help.

One thing about that Magfloat. I used to use one a long time ago, and found it was a poor glass cleaner. With each pass, the bristles remove a little algae, but not all of it. So you run it back and forth until the glass looks clean, but it isn't truly clean. There's still traces of algae on there, which will rapidly regrow to visible amounts, or even serve as a convenient substrate for other types of algae to grow. Try running your fingertips on the inside of the glass after a Magfloat cleaning, you can usually feel the remnants.

So now I roll up my sleeves and scrub with a Mr. Clean Magic Eraser (the original variety with no soap or add-ons), keeping one finger on the glass as so I can feel when the glass is squeaky clean. This takes more time and effort, but it slows reappearance of algae enough that I usually save labor in the long run. You might try more thoroughly cleaning one spot and see if this works out the same for you.

· Registered
1,078 Posts
Overdose on CO2. Ha, that's pretty hard to do since you'd notice your fish suffering. Plus remember that the flux of CO2 exiting the surface of the tank increases as the concentration in the water increases.

As for cleaning the sides, I use a simple razor Blade. One swipe and its all gone. Then water change it out.
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.