[Teeman]

Hi everyone,
I have read alot about the whole lighting issue and just can't seem to come to a conclusion.People still go by the wpg formula but its my understanding that with the HO bulbs you can't use the same formula is this wrong thinking?I currently have a 80 gallon tank which is 24 inches deep.I have 2 T5 Ho 54 watt 10,000 daylight bulbs in my fixture aswell as a high reflector.My plants just seem to survive not really thriving.I've started injecting Co2 the past couple weeks aswell.I supplement with Flourish and also have Flourite as a substrate. So according to the wpg I would be way under would I not??Any suggestions or information is greatly appreciated!

 

[DarkCobra]

T5HO is much more efficient than anything the watts-per-gallon "rule" anticipated.

I have a dimmable 2x39W T5HO fixture on top of my 46G bowfront, with some good Icecap reflectors. With it turned all the way up, it almost reaches the max light plants can use; beyond which photosynthesis saturates and can go no faster.

Take a look at this chart:

http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html

Assuming your bulbs are 24" above your substrate, you have about 90 PAR; which puts you in the high light category. I don't know your real bulb to substrate distance, so you'll need to check the chart for yourself to get a more accurate number.

With high light, plants have voracious appetites for CO2 and all other fertilizer nutrients, that must be fulfilled.

The nutrients required in greatest quantity are the macros; nitrogen, phosphorus, and potassium (NPK).

Required in lesser quantity, but equally important are the micros; there's a long list including iron.

Flourish supplies only micros. Flourite supplies only iron. You're not feeding your plants any of the macros at all. They get some from fish waste, but for high light, it's terribly insufficient.

In short, your plants are starving.

You'll need to make a decision whether you want to increase your fertilization, or reduce your lights; and then we can take it from there.

 

[Teeman]

Hey thanks for the quick reply!Very informative and straight forward.Yes my light would be 24 inches to the substrate,just measured it.So I will do some research on supplementing NPK.Is there a all in one type of fertilizer that would do the trick or just have to individually supplement?

 

[DarkCobra]

As far as commercial liquid fertilizers, like the Flourish you're already familiar with, there isn't a true all-in-one; because putting concentrated iron and phosphorus in the same liquid causes them to react, forming an insoluble substance that does plants no good.

Most of us high-light folk use a dosing system called EI (Estimative Index). It involves adding all nutrients in excess of what the plants will use, rather than guessing or experimentally determining what plants actually need. Of course, the excess nutrients build up in the water, so EI also includes a 50% weekly water change to remove enough of the excess that it can't build up to harmful levels.

While EI can be done with any fertilizer, the commercial liquids get expensive quick, especially in a hungry 80G high light tank! That's why dry ferts are popular. $30 of dry ferts will be enough for years, at a tiny fraction of the cost of any commercial product.

The basic instructions for EI with dry ferts are here:

http://www.plantedtank.net/forums/fertilizers-water-parameters/21944-_dosing-regimes_.html

I buy my dry ferts here:

http://www.greenleafaquariums.com/

There are other EI guides, and other sources for dry ferts. But now you know the magic words to search for to find out more. Take some time and read up. We'll answer any specific questions you have.

 

[willknowitall]

good effort there, darkcobra roud:

 

[Teeman]

Hey darkcobra thanks for all the advice.Have been on a few other forums and would have to wait days before someone replied.Thanx for the quick overview and starting me in the right direction!

 

[DarkCobra]

Sure thing, Teeman. Welcome to TPT.

I'll continue to monitor this thread for a while for follow-up questions, don't be shy if you have 'em.