Frustrated with cyanobacteria

[CassCats]

My betta's tank has had it before. Given the size i found it easier to tear the tank down and redo everything.

Sterilized everything. Sand, rocks, glass, everything. Used boiling water.

Now yet again, cyano has come back!

I had removed floating plants before because they obstructed flow, ive increased the flow and surface agitation.

But here we are again. Cyano taking over the hornwort!

Checked my parameters to see if there was a spike in anything, and nope very stable.

Tank size: 2.5 gallons (i do plan on upgrading this though)
Filter: DIY bottle sponge filter, air powered.
Ammonia: 0
Nitrite: 0
Nitrate: 5

Water changed 95% weekly with about 20% changed daily.

No ferts used.

Lighting is the kit LED from TopFin 10g, nothing crazy.
Light time: 6-8 hours

Plants: Hornwort, java moss, christmas moss, weeping moss, dwarf hairgrass

Residents: just 1 betta. No snails.


I had heating issue when we had a heat wave a couple weeks ago, killed all of the snails in the tank. Cleaned all that out, total water change, watched my parameters after that and all was good until today seeing cyano covering my hornwort, which has been affected from the heat.

I will be removing the hornwort with the cyano, but if this is the second time its come back, i need to figure out WHY.

I plan on a 5 gal for her later this month if we find out good news with my husband's job, so i dont want to find the cyano find its way in THAT tank too.

 

[Byron]

First, the cause of cyanobacteria is organics in the presence of light. Water movement does not "cause" it.

From the photos I would wonder about the light intensity. I had cyano once in a 10g tank that was an experiment...no filter, no light. It sat in front of a west-facing window and I found mild cyano kept occurring on the back glass closest to the light. The organics are obviously there in any tank with live fish being fed. It is asier to control tanklighting. One aspect is duration, make sure it is the same every day. The idea behind this is to establish the balance of light/nutrients so the plants benefit but no more. Your water changes should deal with organics; make sure you clean into the substrate, and keep the filter well cleaned.

 

[CassCats]

First, the cause of cyanobacteria is organics in the presence of light. Water movement does not "cause" it.

From the photos I would wonder about the light intensity. I had cyano once in a 10g tank that was an experiment...no filter, no light. It sat in front of a west-facing window and I found mild cyano kept occurring on the back glass closest to the light. The organics are obviously there in any tank with live fish being fed. It is asier to control tanklighting. One aspect is duration, make sure it is the same every day. The idea behind this is to establish the balance of light/nutrients so the plants benefit but no more. Your water changes should deal with organics; make sure you clean into the substrate, and keep the filter well cleaned.

Would it be worth raising the light so it isnt as intense?

The substrate is vacuumed every water change. Hornwort is a debris magnet though so perhaps ill toss it regardless as further prevention.

I mentioned water movement as a few sources mentioned a cause could be lack of circulation, and last time i had it, it attacked my floating plants horribly. There was no surface agitation because the salvinia grew so dense.

My betta is spot fed, so i try to keep wasted food to a minimum. She gets up to 5 pellets daily, or a few flakes individually fed to be sure she eats them right away. Frozen foods also fed individually by hand.

 

[CassCats]

Actually. I got some indian almond leaves and alder cones in the tank. Given the size, is this a possible cause of excess organics? They do create the normal fuzz something aweful in this tank with no snails to eat it

 

[Byron]

Yes, leaves decomposing are increasing organics. Any living matter that dies decomposes and that is organics.

On the light my first reaction woould be to get floating plants, sommething like Water Sprite wold be idea here. Bettas naturally live among the dangling root masses of this plant, and they grow rapidly and spread and this would help with the light below. Of course, cyano can be a mess on floating plant leaves, as you say.

Some "information" mentions water flow as causes for cyano and algae, but this is not the cause of either.

 

[CassCats]

Yes, leaves decomposing are increasing organics. Any living matter that dies decomposes and that is organics.

On the light my first reaction woould be to get floating plants, sommething like Water Sprite wold be idea here. Bettas naturally live among the dangling root masses of this plant, and they grow rapidly and spread and this would help with the light below. Of course, cyano can be a mess on floating plant leaves, as you say.

Some "information" mentions water flow as causes for cyano and algae, but this is not the cause of either.

Ill find a floater for the new tank then. I have salvinia but its not doing great and i worry about the light level the hairgrass sprouts will get.

Ill remove the alder cones and Indian almond leaves too then

 

[BoningKnife]

I'm having the exact same issues as you at the minute. Having read Byrons (I don't know how to tag) response here. I am definitely guilty on the lighting routine. I'm forgetful so the times my lights go on and off is a bit all over the place. Just fitted a timer today so we will see how that goes.
I was worrying about flow as well cause I have drastically reduced mine, glad to know that's not the problem. I think I need to get a bit stricter with almond leaf use, I just sort of chuck a few in every now and then and then occasionally remove some but I'm probably letting some stay in longer than they should.

 

[Byron]

Yes, light is certainly one aspect, along with the organics. Blackouts are often suggesteed, but if the organics are not dealt with, as soon as the light returns so will the cyano. When I had it in my 70g, I reduced the light by one hour (down to 7 from 8 hours), loosened all the cyano with my fingers and after it had sunk to the substrate vacuumed it out with the 75% W/C, dug into the substrate, cleaned the filter. By the end of the week it was returning, but I was pleased to see not as much, so same "treatment" that week. Same the next. Each week it was back less so I knew I was getting a grip on it, and after I guess five weeks, gone, and never returned in the three years since. I also stopped the plant additives for those weeks as that forced the plants into using the natural organic nutrients more.