Algae and Unheated or low heated tanks

cichlid-gal

New Member
So...I have about 4 unheated tanks.  They are just running at room temp which ranges from about 70 degrees to 72 degrees.  All of these tanks had previously been more warm water tanks (in the range of 78-79 degrees), all tanks were cycled, stocked and healthy.  Since changing stock and making these tanks into cooler water tanks I'm having algae show up in some of them.  Just wondering if this is something that happens more often in cooler water tanks or possibly there is something that causes it.  I tried to search info on this but kinda came up empty handed as most articles on BGA indicate high nitrates or low nitrates, no flow, or excess light.  I have pretty much ruled out high or low nitrates and flow issues as all tanks are well filtered.  I have been monitoring the nitrates for a couple of weeks now in these tanks and they are pretty static.  I have not changed foods only fish and water temps.

The algae is dark green but it is not necessarily slimy or sheeting in the tanks.  It is attached to rocks (mostly seriyu stone) but also on some river rock.  It appears thick and my shrimp like it so I'm uncertain about whether this 1st one is actually blue-green algae.
Water parameters in this tank are 72.1 degrees, PH 8.0, nitrates 30ppm before water changes.  Water changes are 50% once a week.  Lights run 9.5 hours a day.  

algae on seiryu stone


The below is what is growing on the river rocks (green and some black) and showing up in the sand in that same tank.  I do have a high light on that tank but I have raised it up to decrease the amount of light in the tank overall.  I also have a powerhead that runs from the right side of the tank shooting down the front of the tank across that section of sand.
Water parameters in this tank are 71.6 degrees, PH 8.0, nitrates 20-30 ppm before water changes.  Water changes are 50% once a week.  Lights run 9.5 hours a day.

algae on river rock


sand showing green


Does anyone have any experience with algaes and cold water tanks?  Or is this just a lighting issue?  I have been hesitant to change the lighting schedule as I have plants in these tanks.  Any input would be appreciated.

Thanks.
 

MRTom

New Member
The first one doesn't look like blue green algae. It looks like just another kind of diatom algae. Snails and amano shrimp should help make short order of it... but I prefer to keep it as long as I can as I find my smaller fish constantly grazing on it.

For the second algae, could you do an ammonia test? I wonder if there is a problem with ammonia shooting things out of order. Also, are you fertilizing the tanks? And have you seen any outbreaks of black beard algae in the tanks yet?
 

cichlid-gal

New Member
Thanks Tom. I did an ammonia test...0 or minimal you know how those stupid things read.

And I hadn't thought of the fertilizers Tom. I've been using Flourish Root Tabs in this tank in the sand area for the plants. Really no water column ferts to speak of, maybe trace once a week dosed at like 3ml for the tank. I wonder if its the fertilizers?

I haven't had black beard algae in my tanks but this 33G long was a used tank and the old filters on it came in with that on them. I haven't used the filters on the tank and the tank was cleaned really well before use so not sure about that either. Right now the black is just on the rocks and pretty limited, hopefully it will stay that way.
 

MRTom

New Member
I was just at wetspot today, and noticed several tanks with that same black there. I see it everywhere small sand is used for a substrate... So I wouldn't worry about it for now. I'd revisit light duration and ferts if things get out of control.
 

cichlid-gal

New Member
Thank again Tom. Yes, I'm thinking I will change the lighting on this tank and go to 8.5 hours and see if that helps. I'm also going to watch how often I put the root tabs in. In my warmer water tanks the root tabs go in once a month and I don't see this occur in my sand based substrate (all parameters are the same as this tank other than the temperature of the tank) so I'm wondering if because its a cold water tank the plants grow slower and therefore have less need for the nutrients and then they just become excessive and the algae starts to grow. Something to do some research on I think.
 

MRTom

New Member
Yep, great research topic. Another possibility: higher oxygen in the water at lower temps means more active fish, leading to more waste, and that waste accumulating in the substrate more quickly. Yet another angle to consider :)
 

LuminousAphid

New Member
i have been having some issues with a couple of types of algae in my cooler tanks tooo. i have noticed a lot of BBA and quite a bit of brown diatom, but nothing looking like what you have there.

One easy way to solve your algae problem is to realize that it is not the algae which is the problem, it is your distaste of the algae that is causing the problem. When you realize this and learn to love the algae, you will be free from its influence over your happiness with your tanks.

Had to get a bit zen for a moment. But seriously, I just try not to sweat it and eventually it seems to work itself out. UNLESS it's cyanobacteria, that stuff is really bad and I hate it. But it's not actual algae, so I still say just learn to live with the algae and you will be much happier.


Anyway on topic, yes I feel like something with the lower temperature must allow algae to grow better than at higher temps... Tom had an interesting idea but I bet it has more to do with the metabolism of the algae rather than the fish and waste produced. I have a feeling that, just like plants, algae has an optimal temperature for metabolizing its food and growing, which is probably closer to room temp than the 80 that some of our tanks are kept at. Maybe the cooler temp just allows them to eat and grow faster, so they take over more easily.
 

LuminousAphid

New Member
also, changing the lighting is probably a good idea too... the plants won't be changed much if you cut back but you may significantly cut down on algae. or if you are already on the low end, maybe up the light cycle so the plants have a chance to compete. also i would add some more floating plants or something like guppy grass which will really eat up nitrates
 
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