Growth on driftwood

Colin_T said:

Most sponge filters create a small amount of current so there would only be a small amount of water movement. Depending on the tank size, this might be sufficient if the aquarium is small. However, if the aquarium is large then a single sponge filter won't provide much current.

If you have active fish that like a current and a medium to large tank then you could add a power filter to improve circulation. However, in a small tank or if you have fish that don't like fast moving water, a power filter would not be beneficial.

An airstone run off an air pump can be used to circulate water as well.

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CassCats said:

Cyanobacteria isn't edible to fish, it's not a real algae. It's a bacteria that behaves like algae.

It can affect plants but if it's not on your plants, good. Increase circulation to prevent more of it and reduce lighting to 6 hours a day and/or dim the lights if needed.

Don't worry too much about CO2 levels in a low tech, the plants you have don't need it and less oxygen/less circulation is a bigger concern.

Also heads up on mollies in a 15 gal, they get big and ideally should be in a 30 gal plus. Balloons stay smaller but are prone to health issues, so careful on that.
My old girl to give you an idea of how big the domestic morph mollies can get
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CassCats said:

High parameters can also contribute to it.

It's difficult because you've got nitrates in your tap already, but you have a couple options.


More plants, especially fast growing ones like hornwort, floating plants, water sprite, brazilian pennywort, elodea, etc. Vals and crypts are slower growers so won't use as much nitrates as quickly as you'd need them to.

So, you have 3 options and you can even do a combo of them:

1) quadruple the amount of plants in that tank. You can out compete algae ironically by often adding way more plants.

2) create a separate reservoir of water with a light and airstone, say a tote bin or a big old rain barrel. A week before your water change, fill it with water from your tap. Have it full of duckweed or water lettuce to eat up the nitrates in the tap water. Use that water then to refill your tank during water change.

3) get an RODI system, it will strip your water of nearly everything in it. They're expensive, but sometimes necessary. Again, you'd be looking at a reservoir system with this potentially if you got larger tanks at all, but this water can be further adjusted with GH, KH, and pH to where you need it to be for your fish.

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CassCats said:

High parameters can also contribute to it.

It's difficult because you've got nitrates in your tap already, but you have a couple options.


More plants, especially fast growing ones like hornwort, floating plants, water sprite, brazilian pennywort, elodea, etc. Vals and crypts are slower growers so won't use as much nitrates as quickly as you'd need them to.

So, you have 3 options and you can even do a combo of them:

1) quadruple the amount of plants in that tank. You can out compete algae ironically by often adding way more plants.

2) create a separate reservoir of water with a light and airstone, say a tote bin or a big old rain barrel. A week before your water change, fill it with water from your tap. Have it full of duckweed or water lettuce to eat up the nitrates in the tap water. Use that water then to refill your tank during water change.

3) get an RODI system, it will strip your water of nearly everything in it. They're expensive, but sometimes necessary. Again, you'd be looking at a reservoir system with this potentially if you got larger tanks at all, but this water can be further adjusted with GH, KH, and pH to where you need it to be for your fish.

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CassCats said:

Yes that'd be fine to get the fish slowly used to it, because a shock from high nitrates to low can also mess with their health too, ironically.

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Joybutlookslikedelusion said:

Ok also another honest curious question, if I leave that reservoir water wouldn't the plants in there use the other nutrients particularly the calcium in my liquid rock water lol or I am overthinking it. Has anybody done this before or have you?

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CassCats said:

They could use some of the nutrients, but high nitrates is way more harmful to the fish than losing a little bit of calcium for the plants. You can also add calcium to your tank after as well using various additives.

Reservoirs are something many people in the hobby do for various reasons. Many people use RODI for different things and have water prepped ahead of time to use for the water changes.

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CassCats said:

They wouldn't take out enough calcium that'd affect you anyways but yeah, if you've got the space for it, I'd go the reservoir route.

Sometimes our tap water can give us challenges, I hear you on that one. Mine has unstable pH, over 7 days pH rises from 6.4 for 7.6 and makes it dangerous for my fish during water changes, so I've got to use a pH regulator to keep it stable between changes. Costs about $30 every 3 months, so not brutal, but definitely not something I'd like to pay for the fun of it lol but I've lost a tank full of nano fish when my pH crashed without notice because they did construction on my water pipes on our street which changed my pH. Downside, my pH regulator is phosphate based, and it increases algae like no tomorrow. Luckily, I'm not worried about most algae, as long as it's not cyanobacteria, that's a problem "algae".

Sometimes, we gotta work around things. In an ideal setting, we wouldn't need to adjust our tap water in any way. Nitrates being in it can be really frustrating, but there's ways to work around it.

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CassCats said:

Well, it can be from both, one or the other, or more likely a combination of the two. Cyanobacteria likes to hit areas with limited circulation, so by increasing flow, you are reducing the chances of it happening, and by reducing nitrates, you are helping to starve it out as well.

That's the thing with these glass boxes, they're all a little different from one another, even in the same household you can find one tank behaves different than another. Algae and Cyanobacteria issues are one of those things tied into balance, and balance in every single aquarium is unique so there isn't a 1 answer for all of them. It takes some tinkering and trying out the solutions to find what the problem is for that particular glass box and fixing it. Sometimes it's as easy as reducing light times, other times it can be a lot more brain work to figure it out. It can be trying and frustrating while trying to find that balance too.

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