CO2, CO2 and CO2.
Is this a DIY CO2?
You need at add CO2 so that there is 30ppm or there abouts all day, not just the latter 1/2 of the lighting cycle.
High CO2 between 0-4 hours of light is the most important stage of CO2 dosing.
So you can start dosing CO2 about 1 hour prior to the lights coming on.
Then shut off CO2 at about 1 hour before they shut off.
Hair algae tends to be due to low poor CO2.
Folks have issues with measurement of CO2 as well.
Some might have a good KH/pH relationship/measurement that works, whereas another person might have poor test methods/non carbonate alkalinity, took only one measurement at the end, not the start of the day for CO2 etc.
You need to know you have enough CO2 for the 10 hours, not just one time point.
Folks insist to me all the time they have good CO2, then..............they check early, they do not, it was only at the latter half of the day.
Good flow through a CO2 reactor, or flow by a diffuser will help mixing better.
Adding high CO2 levels only during the day allows you to add more with far less risk to fish, you can add it right before the lights come on to make sure there's plenty of CO2 from the start.
There is a lot more to CO2 than one single measure, it involves temporal issues, 24/7 vs 10 hours per day effects on fish, O2 production, current, filter and flow dynamics, CO2 gas mist, good reference methods to get a good measure on CO2.
Unlike light, nutrients, which are much easier to measure and dose, CO2 is very empheral.
The range can vary 20ppm in a single hour.
NO3? About 0.1-0.2 NO3 ppm per hour at most. Not much compared to CO2...........
I have been inducing hair algae lately to 4 tanks. These tanks had no issues prior(good plant growth). I just shut off the CO2 in two and turn it down in the others. Each tank has the CO2 come on about 1 hour prior. Took about 1 to 2 weeks.
I've since turned the CO2 back on to normal levels, about 30-35ppm.
I use a KH reference and then a pH meter.
This yields no interference due to tank water and allows accuracy to about 1ppm CO2.
When this was done, the hair algae has stopped growing.
While it does not show what happened in your tank, it is very suggestive that CO2 declines will cause hair algae, two species Spirogyra and Cladophora in particular. Carbon is linked to NH4 and NO3 metabolism, P, S, K+ etc.
So the downstream affects can be diverse and problematic.
Serious long term CO2 issues induce BBA, can exacerbate GW, GSA, Staghorn in conjunction with input cycling of waste like NH4 from fish food/feces/substrate sources/gravel upheavals etc.
If you want to look for cause in algae, the CO2 is something that must not be brushed aside. It accounts for most of the algae issues, about 95% of of them I've seen and addressed.
Note: if you reduced the luight, say to 2 w/gal, the algae and issues will go away.
More light = more CO2 demand.
So if you are not quite able to get enough CO2 in there, this will help.
Do not do siestas, they don;t work and they do not help.
The only reason they might help: it gives the poor underpowered CO2 system to build back up enough CO2.
Plants and algae are similar in the light responses, with the advantage going to the algae, not the plants. They are smaller and faster in terms of uptake, lack any transport system requirements, demand far less nutrients than plants over all. They do tend to light higher light than plants as they have less demand for nutrients, light is the only thing that limits their growth in most cases absent of plants. Plants remove some of the signalling cues, namely variation in CO2 and NH4, espeically under higher light.
But if the plants do not have enough CO2, then they will not remove enough/as much NH4, not produce enough/as much O2, etc.
These things are linked.
Regards,
Tom Barr
