Mortis said:
Well my tank is 18" long and Ive got 2 x 2foot 14W T5s over it = 28 watts over 60 litres. Probably a bit lower since about an inch of the tubes stick out at either end. Still, it is around 1.9 wpg.
Yeah but you see watts don't grow plants and algae, PAR does. So the linear distribution of PAR along those 18 inches is the same as if the tank were 2 foot long. Also, the distance from the bulb to the plant determines the energy level being absorbed. If you want to speed your recovery then turn one of the bulbs off for now. Light is the source of all algae problems so you must always include this factor in any troubleshooting.
Mortis said:
The idea with cuting off CO2 and using excel as the primary CO2 source is that cladophora which can utilise CO2 cannot deal with Excel as the only source of CO2. Does this make any sense ?
Well not really. One of the possible triggers for Clado is low CO2, so it can hardly make sense to lower the total CO2 from what you have now. Algae are 1000X more efficient at feeding CO2 and nutrients, that's why they thrive when these values are too low for the plants. It never makes sense to lower them even more because you will then cause more problems than you solve. You cannot starve algae this way without first annihilating the plants. They will simply use the CO2 that is dissolved from atmosphere, while the plants will suffer terribly from a sharp drop in total CO2 levels. Excel does not produce nearly as much CO2 as the gas injection does, so instead of cutting the CO2 injection, simply add more excel and use the algecidal properties of the product to do the dirty work. More Excel also will add to the total CO2 uptake of the plants making them grow faster and thereby enabling them to resist the algae. Again, trying to eradicate algae outside of the context of plant health is a flawed policy. Like vultures and hyenas, algae understand the language of tank health. When the tank is unhealthy they attack and thrive. When the tank is healthy they retreat. You want to think about maximizing plant health first, not about killing algae. You want to think about adding maximum CO2/Excel tolerable by the fauna, and maximum nutrient levels with maximum flow and maximum water changes. All this while using
minimum lighting. Afterward, these values can be reduced to within reason. This is a simple blueprint, but people freak out because they lack the fortitude to go all the way. Half measures caused by doubt tend to prolong the agony.
Mortis said:
Also, please explain what you meant about the moss not turning brown being a nutrient issue ?
Well normally, one of the classic CO2 failure modes is the decay and cell death due to poor Carbon uptake. Clado, like most other algal forms have multiple trigger mechanism such as both (or either) Poor CO2/Poor nutrients. So it can be a combination of both causes or just one of those. This forces us to guess whether it's both or either, making troubleshooting more difficult. That's why it helps to understand the other modes of CO2 failure. That way we can use process of elimination. We know that poor CO2 causes cell death and it also triggers hair algae (which is the most straightforward of all since it is strictly CO2 related) or staghorn algae (which isn't quite as straightforward but still a pretty good indicator of poor CO2). So we look around the tank to see if there are other symptoms of poor CO2. It's unlikely that poor CO2 would "only" cause Clado - there generally should be other symptoms, such as browning of leaves, translucency, mushiness, lower leaves falling, surface scum, holes in leaves, black spots, deformation of leaves and other structural failures. If we do not see any of these other symptoms, or if there is only minor occurrence of other symptoms, then it's a pretty good bet that
acutely poor CO2 is unlikely and that it's more of a nutrient issue, perhaps only
exacerbated by
mildly low CO2 or by poor flow in that local area.
This is probably about as clear as mud....
Cheers,
