Specs:
26g Bowfront
65w PC Light (8.5 Hrs/day)
DIY C02 (2 2L bottles) new bottle every 5-7 days. D.C. stays green using 5dkh solution. As soon as I get my Rex-ulator order I will be going pressurized (next week)

When I started dosing my 26g about 8 months ago, I was using this as a starting point:

_Dosing Regime's_ - The Planted Tank Forum

20~40gal
50%H20 change-weekly
+/-1/4Tsp-KN03 3x a week
+/-1/16Tsp-KH2P04 3x aweek
+/-1/16Tsp-K2S04 3x a week
+/-5ml or 1/16Tsp-Trace 3x a week
+/-1-2ml-Fe/Iron 3x a week

I know the EI thread here in this Forum, the extra K2S04 is not included in the dosing recommendations.

I understand that the KN03 and KH2P04 pretty much cover the pottasium requirement. Should I go ahead and stop dosing the K2S04?

I currently dose the following on this tank:

1/4Tsp-KN03 3x a week
1/16Tsp-KH2P04 3x aweek
1/16Tsp-K2S04 3x a week
1/16Tsp-Trace 3x a week
2ml-Fe/Iron 3x a week (Flourish Iron)
Excel 2ml daily

Growth is excellant, however the last month I have started seeing a small amount of BBA. Not sure what is causing this. My D.C. never changes from green even with the 5dkh solution.

5 dKH distilled or deionized water in the drop checker would be green at about 40 ppm of CO2. I don't think DIY CO2 will ever get that much into the water, so I think there is something wrong with how you are using the drop checker. It could be that the KH of the water is much lower than you think. It could be that you aren't using distilled or deionized water. But, BBA usually means either low concentration of CO2 or water circulation in the tank that is not adequate for keeping CO2 enriched water available to all corners of the tank.

I actually have two different solutions made up that I use in my DC. One is 4dkh and the other is 5dkh. I check the solutions each time I change the solutions in the DC. They are both made with deionized water. When I change the solutions, I clean the DC well, followed by a rinse with either the 4 or 5 dkh solution and add 3 drops of the Meth Blue. Is is a Red Sea DC.

When I use the 4dkh the DC getts pretty yellow, when I use the 5dkh it stays a nice green color. I don't let my yeast solutions run very long to try and keep the output as consistant as I can. The DC is on the opposite side of the aquarium than the reactor.

I am using a homemade in-tank reactor. 1 1/2" thinwall tube with the C02 entering mid way and a zoo med micropump pumping water into the top of the reactor. Appears to be desolving the C02 very well. I have a very small amount of micro-bubbles that push out the bottom of the reactor. I have the bottom plugged with fairly fine filter material.

Regarding the BBA, my original thought was it was a circulation issue also. I am running an XP3 wide open with a spraybar slightly rippling the water surface. The odd part is, the BBA is showing up mainly on the top plastic part of the in-tank heater and in a couple spots on the substrate. Both areas have enough circulation than you can see the BBA waving in the "wind".

Also, what are your thoughts on the K2S04? Not needed with my other ferts? Any chance the additional Potassium is causing the BBA?

Thanks Hoppy,

Mike

It certainly seems that you do have about 40 ppm of CO2 and good water circulation. I haven't read anything I can recall that suggests that potassium in any quantity leads to any kind of algae. As far as BBA on hard surfaces in the tank goes, when I get BBA it always hits those surfaces as bad as any other in the tank. The only other thing I can think of is routine weekly cleanings - doing those well is also good insurance agains algae attacks. With that I have shot my last arrow!

If you have BBA, you need to describe each aspect of the CO2 system, not just the data from one reading or a DC reading.
While they are useful, they have a long lag time and color reading is tough for many.

I think the water is your asrea should be fairly good as far as KH, so the pH meter would give you better responsive results more than likely.

Also, by the time you measure the CO2, after BBa is there, you may have corrected the issue.

BBA generally will not go away on it's own, however, you can stop new growth or add Excel and manual cleaning/trimming to get rid of the stuff that remains.

While manuy seem bedeviled and in disbelief with CO2 and BBA, it really is solely a CO2 issue, no matter how many folks claim it's something else, they generally have not looked at the their CO2 close enough if they believe this.

I've never once been able to induce BBA with anything else suggested.
Until that day, I'll stick with CO2.

I've also cured every BBA issue going back 15 years using nothing more than CO2.
I spent 3 years messing with BBA, Steve and I talked a lot and spent a long time figuring it out to be sure.

If you have BBA, you will believe anything if simply adding a little bit more CO2 did not seem to resolve things for you.

Some limited PO4, but that decreases photosynthesis, which in turn also limits CO2 uptake and thus demand.

So now you do not need to add CO2, you are now PO4 limited, not CO2 limited at that point.

This example is classic myth/pitfall of equating correlation to cause.
Getting good stable CO2 is 90-95% of this hobby if you use CO2 gas.

Never underestimate it and think you know it all when it comes to CO2.
Only a fool would do that.
I've been a fool a lot in the past on that one.
Now I know better and give CO2 the respect it demands.

Regards,
Tom Barr

Thanks for the inputs guys!

I should have my regulator from Rex in about a week so I won't need to battle the inconsistancy of yeast production any longer. Hopefully that will solve the issue.

The BBA is minimal at this point and I remove any I see during the weekly cleanings and spot with excel. Hopefully I can keep it under control until I get the pressurized system set up.

Oh Yeah,

Back to the K2S04, based on what I dose, should I stop adding additional K2S04? Tom/Hoppy - Is that part of your dosing regimes in your tanks or do I get enough with the KN03 and KH2P04?

1/4Tsp-KN03 3x a week
1/16Tsp-KH2P04 3x aweek
1/16Tsp-K2S04 3x a week
1/16Tsp-Trace 3x a week
2ml-Fe/Iron 3x a week (Flourish Iron)
Excel 2ml daily

I have never dosed K2SO4, and don't even have any. To the best of my knowledge there is enough potassium in potassium nitrate. But, I also have never heard of additional potassium causing problems.

At the risk of being a repetitious bore, I have to say again that there is something else besides low CO2 that causes BBA. I have soil based, non-CO2-injected tanks that do NOT have BBA. (Some do have other kinds of algae, though.)

I also have tanks that do have BBA. The only difference that I can see between the afflicted and not afflicted tanks is that the former might not have as good water circulation, because of my failure to thin out the plants enough, but there could be other variables.

Any thoughts?

Bill

Soil based, non-CO2 tanks presumably have low light intensity too. No aquatic algae does well with low light. Is that the reason why CO2 is not the issue with such tanks?