Light intensity and when to use co2

[Philly33]

I copied this chart from another post. According to this chart I'm at "too high". I have a 90gal with 3x54w Hagen glo t5 ho fixtures. Depth 24", lights sit on top.

How valid is this? I can't find info on this. I've been told watts/gal isn't a true measure of intensity anymore.

What are the signs that co2 becomes necessity? I'm dosing a carbon supplement currently.

I've spent a lot of $ in the past year. That's not an issue. There are so many contradictions. I just want it correct.

Please advise?

 

[jetajockey]

That chart is from plantedtank.net,and it's accurate, it was taken using actual PAR data.

That said, not every fixture is the same, and this chart was compiled using a little bit higher end stuff than the basic on the shelf type fixtures. Something like individual reflectors makes a big difference in PAR so keeping that in mind the chart should just be a basic guideline, ymmv, and with the hagen glo I think you are probably more likely in the medium area.

I have a 3x54w over a 24" tall tank also and it's decent but not extreme in any way.

You'll know when its time to do pressurized co2, either you'll want faster growth or you will have serious light related algae issues.

 

[BBradbury]

Your Lighting Question

Good morning Philly...

Wow! You have a lot of light in that 90G. Having a healthy, planted tank isn't "brain surgery". I've had large, planted tanks for quite a while and follow just three rules:

First, match the plant with the right lighting. I'm a fan of the old "watts per gallon rule". If your plant needs low light, then you need a little less than 1 watt of light per gallon of tank volume. Moderate light plants, up to 2 watts per gallon. Strong light, 3 watts and bright light 4 watts.

The plants need nutrients: There are two sources, either have a lot of fish in the tank or use a commercial fert in liquid, dry or granules. Just dose according to instructions.

Last, you need to change a minimum of half the tank water every week. Weekly, large, water changes replace minerals that keep the plants healthy.

This is what I do. If I can do this, I'm fairly sure anyone else can. The biggest problem I see, is that some waterkeeper's are what I call "water change slackers". They don't change near enough water and not very often. That's the quickest way I know for the whole tank to "go south" on you. If you take care of your tank management business, then you'll have a healthy, planted tank.

Just one, old "waterkeeper's, humble opinion.

B

 

[aqua_chem]

Hagen Glo fixtures have wide reflectors, giving them better spread but non-ideal light directing properties.

This is a good example of why one pictures from an incredibly informative post can skew the actual data. The figures from the chart are for ideal, high quality reflectors. The Glo reflectors are considered "fair" for this comparison:

PAR vs Distance, T5, T12, PC - New Chart

Please read the actual post. Hoppy has put a lot of work into it.

As far as good signs for CO2, excessive algae and/or the presence of BBA are usually good indicator. Crinkled leaves also indicated carbon stunting, which mean that the plants have insufficient carbon to grow correctly.

Another thing to remember is that Hagen Glo fixtures come with riser clamps. You can get probably anouther 6" off the surface using those if you need to reduce light.

 

[ejaramillo01]

That chart is from plantedtank.net,and it's accurate, it was taken using actual PAR data.

You'll know when its time to do pressurized co2, either you'll want faster growth or you will have serious light related algae issues.

Can you be more specific here Jeta? I found really interesting this comment. I would like to learn more about this thopic as the OP...
Thanks

 

[jetajockey]

I just meant that those are the two main reasons one would step into pressurized co2. Either you would like your plants to grow faster or you are having light related algae issues.

Assuming you have adequate lighting and fertilization, your limiting factor is going to be co2, so if you are using a medium-ish light setup and want to step it up, adding co2 would make a significant difference. Same goes if you have too much light and aren't injecting co2, except it will help quell algae issues (that are common in a 'too much light' scenario) as well.

 

[Philly33]

I'm on the fence right now. We live in a world of instant gratification. I want to see immediate results. But, I just replanted and just need to be "patient" for a while. I've only been at this for 10 months. Learning as I go. I will want to explore pressurized co2 eventually. I'm hooked! Thanks for everyone's insight.

 

[ejaramillo01]

I just meant that those are the two main reasons one would step into pressurized co2. Either you would like your plants to grow faster or you are having light related algae issues.

Assuming you have adequate lighting and fertilization, your limiting factor is going to be co2, so if you are using a medium-ish light setup and want to step it up, adding co2 would make a significant difference. Same goes if you have too much light and aren't injecting co2, except it will help quell algae issues (that are common in a 'too much light' scenario) as well.

Thanks Jetajockey!