Since I have turned my hi tech aquarium into a low-tech aquarium I have noticed black beard algae due to I am assuming water changes weekly for the low dose EI dosing that I use. I would still like to do weekly water changes to keep nitrates down. If I used a 5 gallon bucket to do a 25% water change using an 80 gallon per hour pump pointed at the surface how long would it take to de-gas the CO2 out of the tap water?

Your question is hard to answer. No amount of agitation will off gas all the CO2 because there is plenty of CO2 present in the air. The dissolved CO2 in the water will only reach an equilibrium point with the atmosphere. Not to say it will be the same as the atmosphere, but it won't completely off gas to zero.

I want to say you are doing the opposite of what you should be doing. The algae is likely an overdose of nutrients and lack of CO2. CO2 is the limiting factor of a low tech aquarium. Usually, you don't need to dose anything unless you see noticeable deficiencies. Any form of dosing in low tech is something I avoid suggested, especially when just setting up a tank. You should keep up with 50% water changes and stop dosing the fertilizer regiment you are using. That's my opinion.

"Balancing the nutrients is easy. You can rule those out with eI, then move on to the CO2 which is why you have the BBA in the first place.

Regards, Tom Barr"

This has always been my understanding of bba. Co2 related.

I went one month before I started fertilizing again after I took off the co2 and raised the lights. During that time bba started in on the little bit of open substrate I have. During this time my plants began degrading so I started a small version of an ei regimend and the plants bounced right back. To me this means I have a somewhat balance with nutrient dosing. The only thing that makes sense is that I have been doing 50% water changes every week.

I also get that that I can't get rid of 100% of co2 in the water but I can get it to the 3-7ppm that the aquarium has and that's my goal. Hopefully with this method I can keep co2 in the aquarium consistent and eliminate bba growth.

I'm figuring with the pump running in the bucket I can accomplish this with a couple of hours. I'm just wondering if anyone does this?

I don't do this and if I had to, I'd leave the hobby.

If you are having a algae problems, I'd be more inclined to think there is something else going on that is causing the BBA.

EDIT: Here is a excellent ( and lengthy) article from Tom regarding non-CO2 methods. Non CO2 methods - Aquarium Plants - Barr Report I agree with most of it, although I still do water changes because I like clean water and they make my fish happy.

Then there is this video https://www.youtube.com/watch?v=KDdpUe4Olcg from Dennis Wong that has become my all time favorite in regards to algae issues in the low tech / high tech tank. What makes the video brilliant is he explains the differences between the two and why. He doesn't use a broad brush which I find refreshing.

CO2 fluctuations from your tap water are pretty unlikely to cause BBA in a low tech tank, if it truly is low-tech.
More than likely, the problem is that your light levels are higher than you think(meaning you are a little more than low-tech lightwise), which is why BBA is rearing it's ugly head in your low-tech setup. You'd have a deficit of carbon, but adequate light and nutrients for any old opportunist to take advantage of.

What is the tank size, what type of lights are you running(and perhaps the distance from the substrate), and what photo period?

I like Dennis Wong a lot. I'm subscribed to him on YouTube. I'm a fan of how he details things. I have also read tom barrs article before and both the artical and the video are saying the same thing I am; co2 fluctuations are the drivers of bba. During toms no fish waste test he adds 1/4 teaspoon of kno3m and 1/4 teaspoon of kh2po4 per week. My tank is comprised of one sae, 2 otos, 20-30 neocaridina and maybe 100 pond snails and 3 nerite snails. Can't imagine a gigantic bio load here. But I dose 1/16th teaspoon of potassium sulphate 2x week and 1/32 teaspoon of potassium phosphate 2x a week and 2ml of a 5ml dose of csm+b that is a 50% ei 500ml solution meant for a higher tech 10gallon (lol. Looks funny written the way I described that) and NO kno3 because my tap has about 15-20ppm. This is less nutrients than tom dosed but I also added in the fish load so probably about the same. Down below is a screen shot of the video where Dennis says the same.

Spore-

Regarding my light; 60 par at substrate under light and 50ish in the front and back. 30" finnex planted+ 6" above the tank rim with 2-3" of substrate. 8.5 hours per day split by 4 hours. It is a 20long and I dose api co2 booster @2ml per day.

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In my personal experience, for years I've had issues with diatoms taking over my tanks post cycling via the fishless cycling method. Plants would literally be caked with them for weeks which made me not want to keep plants at all as it was a total PITA.

When I decided to set up my 5.5 gallon, I opted to heed the advice of doing more water changes, rinsing filter pads, ect... My 5.5 gallon is going on 6 weeks and my plants are not caked with diatoms. I've seen a few specks of diatoms on the glass and that's it. A completely different experience than I have had in the past.

If water changes with water that wasn't degassed was the end cause of BBA, my tank should be covered with it as I do 3 water changes on that tank per week. It's a small tank and needs more attention than my other 2.

Good luck!

50-60 par seems pretty high for a tank with no CO2. I am not sure that your dose of glut is making up for that lack of carbon either. Since we've already used Tom Barr's advice here a few times, I'll reference his post over on his forum where he gives some pretty low PAR numbers on ADA tanks, and then proceeds to talk about the benefits.

ADA lighting at Aqua Forest and nice low PAr values-who knew? - Aquarium Plants - Barr Report

I would fathom a guess that lowering your light intensity by raising your fixture or using some diffusion method, and possibly shortening your photo-period would help a lot. This would lower the carbon demand, and perhaps removing that limitation from your system will balance things out.

I have seen people with low tech tanks get bba and not when doing water changes so i don't know. I was just figuring this is a simple step to take to avoid it if it works


I read that a few weeks ago. Interesting stuff. I'm stuck on light height but I can shorten duration. I just increased duration by 1.5 hours about a week ago. Granted the bba was already there when I did that. My bba is mostly beaten back because of h202 treatments but I am trying to avoid future growth. I can also kick up the glut dose a little bit. I still think this is a co2 fluctuation thing but reducing the light a little bit probably wouldn't hurt things.

I'm skeptical that water changes are triggering an outbreak of BBA. Too many people (myself included) just dump tap water into the tank without issue.

http://www.aquaticplantcentral.com/f...s/87902?page=1

This is an article I just looked at and it implies a lot of things but the recurring thing it talked about was not enough co2 for the light level and high organics in the water.

My bba is dying away as I treat it with h202 and isn't spreading. I'm thinking this may have been caused by not doing water changes for a bit and not dosing glut. I have since gone back to weekly water changes and dosing glut.

I'll skip the de-gassing of water and just focus on glut and weekly water changes and I'll maintain my current dosing and see where that leads. I'll post updates in a couple of weeks