Water is pea soup green with algae

[AtomicSunfish]

Okay, so I donated my time to a nearby school to obtain and set up a 140-gallon, reef-style aquarium as a freshwater tank for them. It has an overflow box, which leads down to a sump with pre-filter floss and bio-balls for trickle filter (wet-dry) filtration. The water then returns up to the tank via a power head.

The tank is not heavily stocked, housing 3 blue gouramis, 2 angelfish, a blue acara, and a ~5-inch common pleco. It used to house a redtail shark, but it recently died, likely due to poor water quality. There were also about a dozen Endler guppies, which persisted amid the larger fish, but also recently died out, again likely due to poor water quality.

Here’s the problem: the tank water turned green like pea soup with algae a couple months ago, and although I’m trying to help the school, the problem persists. Part of the problem is that, although I trained someone on how to properly clean aquariums (water changes with gravel vac), it appears they were not doing it consistently.

I volunteered my time to do it myself a couple times this month, and I sucked up enormous quantities of dark detritus, which of course is basically fertilizer. The tank is also in a hallway with 24/7 lights on (as required by fire code), so that’s going to fuel algal growth, too. I advised the school to keep up with water changes and gravel vac, as well as to put a blanket over the tank at night to provide darkness, but they haven’t done these things yet. I also added a pothos plant last week to remove nutrients from the water, and it has started growing roots, so I think that will help.

Is there anything else I should tell them? Anything I’m missing? Anything they can do to their sump to improve filtration, like add more filter media, such as sponge material or other media? I really want them to solve this problem, so they can have a nice, big tank in their school.

Edited July 18 by AtomicSunfish

[daggaz]

Did you cycle the tank first??  But yeah, the 24hr lights are the biggest issue on top of zero water changes in a non-planted tank.  

For low maintenance, you're going to have to go with a lot of plants, but even then somebody has to trim the verge on occasion and just keep an eye on things.  Tanks won't maintain themselves. 

I'd redo the substrate to aquasoil, put in a ton of plants, definitely keep the sump, and make clear to the school that the janitors/teachers need to cover the tank at night.  A suggestion here, is to put in a curtain so that this job is always super easy and convenient: just pull the curtain closed. 

 

 

[AtomicSunfish]

On 7/18/2024 at 12:58 AM, daggaz said:

Did you cycle the tank first??  But yeah, the 24hr lights are the biggest issue on top of zero water changes in a non-planted tank.  

For low maintenance, you're going to have to go with a lot of plants, but even then somebody has to trim the verge on occasion and just keep an eye on things.  Tanks won't maintain themselves. 

I'd redo the substrate to aquasoil, put in a ton of plants, definitely keep the sump, and make clear to the school that the janitors/teachers need to cover the tank at night.  A suggestion here, is to put in a curtain so that this job is always super easy and convenient: just pull the curtain closed. 

 

 

Yep, I taught them about cycling, and I seeded the tank for them with BB from one of my tanks. It has actually been running fairly well for over a year, amazingly enough. Until now, the main problem has been diatoms growing all over the glass. I showed them how to use an algae scraper, and things were going ok. They were doing water changes, but not vacuuming the gravel. So, after a year of detritus accumulation and 24/7 ambient light, they got an explosion of planktonic algae about two months ago. I did two 80% water changes with lots of gravel vacuuming. This diluted the algae, but then they grow back. I think the pothos plant will grow nice and big, and absorb lots of nutrients, but it’s still new.

Yeah, there’s only one person (a high school student) trained on how to maintain the tank. They definitely need more people on the team.

[mynameisnobody]

If there is no one willing to commit then you’re fighting a loosing battle. There is no quick fix. Either they commit or they have to deal with an eye sore. 

[AtomicSunfish]

On 7/18/2024 at 7:45 AM, mynameisnobody said:

If there is no one willing to commit then you’re fighting a loosing battle. There is no quick fix. Either they commit or they have to deal with an eye sore. 

So true.

[daggaz]

Just add crocodiles. 

[AtomicSunfish]

On 7/18/2024 at 3:27 PM, daggaz said:

Just add crocodiles. 

It’s only 140 gallons, so let’s just stick with caimans. 

[Markp2483]

Get a uv sterilizer. Run that to get rid of green water. Once that’s gone add floating plants “not duckweed” but something to block light but easy to take out when it over grows. Add a grow light to the sump and  a ton of emergent plants also in sump. Basically try to turn the sump in an algae reactor and keep algae out of the display tank.

[AtomicSunfish]

On 7/18/2024 at 9:15 PM, Markp2483 said:

Get a uv sterilizer. Run that to get rid of green water. Once that’s gone add floating plants “not duckweed” but something to block light but easy to take out when it over grows. Add a grow light to the sump and  a ton of emergent plants also in sump. Basically try to turn the sump in an algae reactor and keep algae out of the display tank.

Excellent ideas! Not sure how much of that the school can afford, but the more the better.

[Beardedbillygoat1975]

You could use a couple green killing machines and use them on a Kasa timer for a couple days and then going forward maybe for an hour every 4-6 hours. They’re cheap and reliable. 
 

Floating plants are great for the excess nutrients. Could put some hornwort in the sump as well. 

[mynameisnobody]

These are all great ideas if you have a willing person to commit to maintenance. Or else, you’ll be in the same boat with same or various other issues. 

[Markp2483]

I think i would also modify the filtration. Wet dry have really fallen out. and filter floss if not changed regularly only lead to by passing the media and then your not really filtering water. Would suggest changing the sump config.  Could do mostly coarse foam like a matala koi filter.  Relatively inexpensive and can go a long time between cleaning. 

   

Edited July 19 by Markp2483

[AtomicSunfish]

Update on tank status:

I went to the school yesterday to install some new equipment, but I’m happy to say that when I got there, all the pea soup planktonic algae was gone! Looks like a couple 80% water changes with thorough gravel vacuuming removed enough detritus to starve them of nutrients and get them to die off, even without a blanket over the tank for darkness at night (which I still want them to implement). It took about a month, but it eventually worked.

Since I was there, I installed more media in the sump: lots more bio-balls, 2 sponge blocks, and a pre-filter on the pump. I also installed a Mean, Green-Killing Machine UV sterilizer in the tank, which I’ll run for a week, just for good measure. But it’s amazing what just removing the fertilizer can accomplish.