You can buy any brand of T5HO bulb. It will be fine to add a 6700K bulb to your current setup. I agree that swapping both actinics would not be a good idea until you get a little more experience and understanding with planted tanks.
Using a DIY yeast generator on a 75 gal
tank is not going to be effective at all in getting the CO2
to the level it needs to be at. Those systems are great on tanks smaller than 30 gal
, but anything larger is just not practical. You would be lucky to see hardly any rise at all in ppm CO2
using the hagan yeast generator. A single hagan system is good for about a 10 gal
You are dosing flourish comprehensive I am guessing (you said flourish) which is a micro mix. It actually contains some Fe
as well, so you may not need to add the other Fe
Keep an eye on your nitrate level - it may become necessary to start dosing N if it is bottoming out under the new light.
I would also suggest you pick up a K
supplement as well... either Flourish K
or API Leafzone would work. If you get leafzone, you could dose much less of the flourish comprehensive, as it contains trace elements and K
Excel is a bit different... It is glutaraldehyde, and is a source of C (Carbon) for plants. It is basically used in lieu of a CO2
injection system (which also provides C), but can be used in conjunction from time to time as a prophylaxis for algae.