Re: New 4FT. Low maintanance. Hopefully
jay said:
Intriguing stuff. Really need to stabilize my Co2 then. Keep it at 30ppm, I have it going 24/7 with good surface movement.
I reduced my lighting, should I have bothered?
Just got 2 bulbs working at the moment for 8 hours, it was 10 hours with all for on for 4 hours in the middle for a quick burst of light. I'm still dosing 10ml TPN+ and 4 squirts of Brighty K. Should I keep this up or increase?
Just think if my lights and dosing is on point, then once I've kept the co2 consistent then the algae should go. (Along with using my toothbrush
)
30ppm CO2 has become a Holy Grail of sorts. Very few actually have it despite their dropchecker readings. Reducing the lighting always helps since it lowers nutrient uptake demand. Stability could be an issue in which case as you say, you'd just have to maintain consistent CO2 levels for a few weeks and the algae would fade away.
There are other possibilities however. The burst of light could actually be where the problem occurs. A lot of people have difficulty with the relationship between light and CO2. Both are inextricably linked because photosynthesis fundamentally involves the use of light energy to separate carbon from CO2. The amount of available CO2 must therefore match or exceed the available light energy. If this equation is balanced with 2 bulbs and then, when you double the light energy by illuminating 2 additional, bulbs then you also must provide more CO2 for the duration that the 4 bulbs are burning.
It is extremely doubtful that you can double the CO2 concentration at the time the burst starts. In all likelihood the CO2 level drops as the plants attempt to uptake more as a result of the extra brightness. The only possibility would be if you were for example supplying an excess of CO2, i.e. more than the plants could use, prior to the burst. This would then build up a "reserve" in the water column with which the plants could then use when the demand increase via the burst. The fact that you have CO2 related algae is a strong indication that this is not happening.
So if you assume that your flow is good and your distribution patterns are adequate, and if you assume that the injection rate is steady then there are only two remaining possibilities:
1) The basic injection rate is too low to supply sufficient concentration levels even with the reduced lighting and therefore Carbon fixation failure is occurring throughout the photoperiod.
2) The basic injection rate is adequate for the basic level of lighting offered but insufficient for the burst level of lighting. Carbon fixation failure is occurring primarily during the burst period.
If you are suffering possibility number 1) then you need to increase the injection rate to high enough levels to sustain carbon fixation not only during the basic light period but as well as during the burst.
If you are suffering possibility number 2) then the issue is most easily resolved by eliminating the burst, but if you wish to keep the burst then the rate has to be increase.
You might also wish to consider adding the Excel in conjunction with (or in lieu of) injection rate increase. This gives you more CO2 as well as algecidal properties. The bottom line is that you need to get higher CO2 concentration levels in the tank by hook or by crook. As the plant biomass increases your problem will only become more acute.
With increased CO2 come the demand for more nutrients so the dosing adjustment will depend on which solution is applicable. If you choose the merely delete the burst then no adjustment to the dosing scheme is necessary as the nutrient uptake demand will actually fall. You have not reported any other type of algae therefore there are no other obvious nutritional deficiencies other than carbon.
If you do increase the CO2 levels either via Excel or injection rate or both then there is a possibility that you will require more nutrients since more CO2 drives more nutrient uptake. However it is not clear at this point since we cannot really tell exactly what your uptake rates are or even reliably tell what the nutrient levels in the tank are. Algae due to nutrient deficiencies are easy to fix since all you do is add more, so I wouldn't necessarily change the dosing yet. Fix your CO2 problem first and any additional deficiencies will then be revealed.
You may be interested to know that Brighty K, whose active ingredient is essentially KCl (Potassium Chloride) and basically duplicates what already is available in TPN+. It's up to you what you choose to dose but it is clearly redundant. You may wish to consider deleting it due to cost.
Hope this clarifies.
Cheers,