Random questions

The "need" part is directly related to how much light you intend to use.
This thread covers that much better than I could(and probably in far fewer words).
http://www.plantedtank.net/forums/showthread.php?t=107303

Might as well do this one also: http://www.plantedtank.net/forums/showthread.php?t=184368

I would say no on both but add that some caution might be good. Depending on how you feel about algae, you may need to be careful not to get too much light. We all have different levels of what we like/don't like. I am not bothered by having algae in the tank. It looks very natural to me and as long as it is not a problem, I don't fight it. After all it is just a different type plant. But if you are bothered by algae, then it is easy to get too much light and not have enough CO2 present to promote good growth.
Balance is needed in ferts, light and CO2. Finding the correct level on these is tricky as all tanks are different making it hard to pin an exact number of all the things involved.

The plants you listed do not require pressurized CO2.

The plants you want to use and the lights you end up buying will determine if you need pressurized CO2. My 80 is dirty with 2 T8 bulbs so I don't use or need pressurized CO2.

It's not required, but it will certainly help them grow.

kenshinH said:

The reason why i asked is because i am buying a used 75gal with overflow/sump at CL, i already have an existing 110gal Tall tank high tech , at the moment i dont have the funds to buy another pressurized Co2 for the 75gal, so i am thinking of removing some of the demanding plants from my 110gal and transferring it to the 75gal leaving the 110 without a pressurized Co2, in other words i will downgrade the 110gal to low tech and making my new 75gall high tech.

These are the plants currently in my 110gal: (safe T-sorb substrate)
-Anubias
-Water wisteria
- Ludwigia repens
- Java fern
- Narrow leaf giant hygro
- melon sword
- Crypt bronze
- vals

Click to expand...

All of those plants in the 110 can be grown just fine in medium light without co2...possibly even low light tbh

I think, if you wanted the 75 to be high tech, that its worth your time to just switch where you are injecting the co2 and all.

But I have to ask, why would you want to make the 75 high tech and the 110 low tech instead of just doing the 75 low tech and keeping the 110 high tech? Isn't a 110 just a much taller 75?

If the 110 is low tech, it will mean going into it less and the lower tank will give better
light with the same light you now have on the 110(provided it's not extreem).
Bare in mind that you will almost be doubling your PAR and say you had one of those BML x high PAR rigs..that may blow away a 75. Not the regular BML, those listed as
being higher than their normal ones.
High tech often needs weekly trimming and in a 75, that would be much easier.