Algae or fungus? Need a diagnosis!

[NickNaylor]

Hi everyone,

I'm currently almost a month into my cycle of a 30-gallon freshwater tank. I've noticed what appears to be some algae growing on the driftwood (which I originally thought was just the fluffy white fungus that everyone talks about with new pieces of driftwood that are added to the tank). I wanted to get your diagnosis and advice.

There are no fish in the tank currently. The plants have been in the tank for about 3 weeks and have been doing well - not crazy growth, but they generally look pretty healthy, haven't died on me, have nice coloration, etc.. I'm dosing with Flourish, Flourish Excel, and Flourish Trace as directed on the package labeling (i.e., Flourish twice weekly, Excel daily, and Trace twice weekly). The tank is injected with CO2 using two 2 L DIY CO2 reactors; level is typically quite low (it has maxed out at 9 ppm for a couple of days but usually floats around 4-5 ppm - I am planning on upgrading this to a pressurized system in the coming weeks). My lighting is with a Finnex Planted+ 24/7 light as well as a Satellite Freshwater LED+ light. The former runs 24/7 on its cycle (which provides roughly 6 hours full blast light) while the latter is run manually for supplemental light during the day - usually for 8-10 hours a day at full blast. The substrate is about 30 lb. of EcoComplete, which comes to about a 3 in. substrate at the bottom of the tank.

About a week and a half ago, I added a piece of Mobani wood to the tank. A few days after I put the tank in, I started getting the white film everyone describes, which I wasn't too worried about. Over the last several days, however, this film started to turn into what appears to be clumps of algae.

I've added a picture below and wanted to get your thoughts. Is this dreaded algae? Or is this particularly aggressive fungus? I'm afraid it's BBA, but as this is my first tank I'm not comfortable making a diagnosis, and it doesn't look like most pictures that I've seen with BBA.

As far as I can tell, the growth is limited to the driftwood. I haven't seen it anywhere else, though one of my plants might have some very small dark spots on the leaves. It could also be residue from the EcoComplete substrate as I've had to move the plants around, replant things that come up from the substrate, etc..

I have been monitoring my water quality daily throughout the cycle. My readings from last night are:

pH - 8.2 (my pH tanked to below 6.0 several days ago with a subsequent drop in KH to essentially 0, likely due to tannins from the wood; I addressed this by adding a bag of aragonite to overflow portion of the tank as well as adding 4 tsp of baking soda; my pH since has hovered around 8-8.2)
Ammonia - 0.0
Nitrite - 0.25
Nitrate - 80
KH - 7.0

My nitrate has been hanging around the 80-160 range for the last 5 days. I've tried to manage this with PWCs, but I'm getting so much nitrate from the cycle that I'm having trouble managing this effectively. I've been using 4 Tbs of ammonia solution as my ammonia source. I add this daily (which bumps my ammonia to roughly 4 ppm, which is cleared within 24 hours). I've been thinking of reducing how much ammonia I add daily to reduce the "bioload" and, thus, how much nitrate the tank is producing. However, I'd really like to get the biofilter going strong so that I can somewhat aggressively stock the tank when the cycle is complete.

Other info on the tank:

- I have a Fluval 207 canister filter which runs 24/7.

- The temperature of the tank hangs around 86 (with a heater) - I changed this to 75 today so that I can start getting the temperature down to prepare for the introduction of livestock.

- I've got a 480 GPH power head in the tank. This combined with the output of the filter and the bubble bars provides pretty solid water flow - the plants sway throughout the course of the day, so I don't think I'm getting any significant water stasis which might promote algae growth.

- I have two bubble bars which provide some pretty good bubbling in the tank. I've read that this can make it difficult to get the CO2 level up; I may reduce this later, but I wanted to be sure I was getting enough oxygen into the tank for the biofilter.

Any suggestions for managing this? Hold back on my nutrients/fertilizers for a bit? Reduce lighting? I'm worried that my CO2 isn't high enough to match the lighting and nutrient/fertilizer schedule and I may be promoting algae growth.

Picture of the offending organism (forgive the loose plant - it came out of the substrate overnight, it will be replanted today):

And here's an overall picture of the tank:

Thanks a bunch for your help.

 

[Khuligirl93]

In my aquarium, the same thing happened. It seems almost like the fungus evolves over time to become more stringy and thick. I dont see any algae in your pic though.

 

[Fresh2o]

The growth in the DW appears to be fungus. You could either leave it alone and let it run its course or take it out and briefly boil and/or scrub it. It may come back but will be greatly reduced at best.
I would not reduce the ferts or lights just yet. What I would do is remove the bubble bars. You don't need them. DIY CO2 is being dissipated by the increase surface disruption. You can use the power head to redirect the CO2 bubbles back into the water column to increase the contact time.
You could reduce the ammonia dosing to 1-2 ppm.

 

[NickNaylor]

The growth in the DW appears to be fungus. You could either leave it alone and let it run its course or take it out and briefly boil and/or scrub it. It may come back but will be greatly reduced at best.
I would not reduce the ferts or lights just yet. What I would do is remove the bubble bars. You don't need them. DIY CO2 is being dissipated by the increase surface disruption. You can use the power head to redirect the CO2 bubbles back into the water column to increase the contact time.
You could reduce the ammonia dosing to 1-2 ppm.

Cool, thanks for the input.

To be honest my CO2 is now insanely high (45 ppm or so) as I changed my recipe for this batch of CO2, so I'm going to keep the bubble bars going until the production starts to peter out (though since there's no fish I guess it doesn't really matter too much - the plants seem to be loving it; my hope is to get fish in the tank this weekend if I can get my water stable and controlled). My next major piece of tech is going to be to get a CO2 tank as the DIY is just too variable for me to handle. I'm afraid that once I do get fish in the tank I'm going to gas them, and I'd rather go with the relative ease and precision of a tank setup than continuing with the DIY reactor.

I did go ahead and reduce how much ammonia I was adding daily and actually held it for a couple of days. I think my tank is completely cycled as it can process 2 ppm ammonia to 0 ammonia and 0 nitrites in 24 hours. The main thing I'm struggling with is super high nitrates which is my focus now. I figured the reduction in ammonia dosing would also help with that goal. Despite multiple 50% water changes over the last couple of days the nitrates really haven't budged that much.

A few days after scrubbing the driftwood, some fuzz is starting to grow back but looks more like the characteristic white fungus that people usually talk about with new driftwood. I'll keep an eye on it but I'm not too worried about it at this point.