Hardy mid to high light plants

[the loach]

The tank dimensions are 4 feet long, 18 inches wide and 21 inches tall. (Standard 75g)

Now we can objectively determine the problem.

https://www.amazon.com/AQUANEAT-Aqu...rds=aquaneat&qid=1593718762&sr=8-3&th=1&psc=1
I think this is it I bought it like two years ago. It’s definitely not “low” light. none of my other aquarium lights are as bright as this one

The manufacturer of your LED states it is 1050 Lumen. This is just 150 Lumen more as a 15W 6500K T8 fluorescent.
This equals about 0,2 Watt per gallon. "low light" is defined as 1 Watt per gallon, and "high light" is defined as 4+ Watts per gallon
To top it off, you have a high tank, too, which requires more light. 1 Watt per gallon isn't the same in a 15" tank as in a 21" high tank.

Conclusion: you have well below the minimum requirement for low light plants, even below the 0.5 Watt per gallon to just keep them alive.
To grow low light plants in this tank you would need another 4 to 5 of these Led lights.

 

[fishorama]

OK, I have a 75g, no co2 but no big cichlids either. I have 2 x T-5s over it & have pool filter sand in that tank. According to tl, you have very low light...I dunno LEDs. I call my tank "medium" light.

You can "try" a few stones around the plants you want to grow...But they need to be large-ish & heavy enough to keep them in place if the cichlid wants to move them. If your light is as low as tl says you are extremely limited but for some reason your "go to" low light plants"aren't growing, they are dying. Java fern & anubias should be good in almost any light IME . When I had a bare bottom discus tank with low light (1 T-8 I think) I planted in clay pots... but, as I said, if tl 's math is right I think you're out of plant choices, maybe mosses?

I think you need to choose between the flowerhorn & plants or add some more or higher lighting...

 

[the loach]

With T5's you might well have medium light, what type are they?
Even Java fern and Anubias need a certain minimum amount of light over extended periods or they'll die. I regularly put clippings/whole plants of those to give away in tanks with just ambient light, unless I put them on the window sill they'll die off in a couple of weeks.

 

[fishorama]

I've grown a few plants with 1 T-12 with old style "hoods" over a 55g 20 inch tall tank. (tl, I know you know, lol). I could grow anubias, java ferns, wendtii crypts & rotala "indica". Big swords were just barely ok, maybe slightly stunted but, well, you know I'm not good at ferts In fact when we had a java fern jungle it was with that same hood light, but hard water. I believe I've said I used to give away a plastic grocery bagful to anyone that wanted to try plants.

What about the spectrum of Riptide's LEDs? What little I remember from when everyone was making their own people switched out some colors...for some reason...but they were going for higher than low lighting I bet.

Yes my T-5s, either old HO or NO x 2, is medium light.

I usually suggest not keeping lights on too long, 6-8 hours, but there's the "number of photons theory" too. So lower lighting needs a longer photo-period to get to "enough" light striking the leaves, "sort of" comparable to a bit higher lighting...preferably a split time so less algae is happy...I don't do split time.

I must have brighter ambient light most of the year. (yeah, Cali baby!) I've kept plants in a bucket for more than a couple weeks. Stems were not happy but ferns & anubias, sure.

 

[the loach]

Riptide's Leds are 6500K, which is fine. That isn't particularly important for the plants (more for the viewer) as long as they are between 3000-10.000K.
Your T5's are good to show the comparison, as you have a 75G as well (same height, too?)
2 HO T5's are 108 Watts, and about 9400 Lumen, so about 1,5 Watt per gallon which qualifies indeed as "medium" light. Compare that to the 1050 Lumen of that Led... it's almost a factor 10.

 

[dougall]

Watts used by LED fixtures does not directly equate the the amount of light produced.

Nor does it take into account the overall efficiency of the fixture, nor the actual angle of the emitter.

And lumens emitted by a circular bulb does not equate to the amount of light available for plants (or algae) to use. Remember that reflectors ate needed, and light hitting the reflector and then the bulb will be shadowed.

 

[the loach]

I'm not sure what you mean by that, as I never equated Watts used by Leds to the amount of light produced?
Lumen is a unit, the total quantity of visible light by a source. It does not matter if it is fluorescent, incandescent, LED or something else. I know some LED manufacturers/sellers/fans say otherwise but they're wrong. That is like saying a Dodge going 100 mph is faster as a Pontiac going 100 mph.

 

[dougall]

Stating 1.5 watts of light is medium ?

Watts is not a measure of light.

A bulb saying that it gives off 1000 lumens of light,

firstly only accounts for the visible spectrum of light as seen by the human eye, not that is usable by the plant.

Secondly equates from light being emitted in 3 dimensions, in total, not just that which is actually usable by the aquarium, and us subject to the inefficiencies of whatever reflector is being used to direct the light towards the aquarium

 

[the loach]

You are right about that, but I'm sure you know what I meant. I did put medium in parenthesis. It's the "Watts per gallon" guideline, I didn't come up with that. Sure it is rough (doesn't account for depth, or bulb length/type, for one) but it works very well in the home aquarium and there is no need to complicate it for hobbyists.
For your sake, we can convert it to "Lumen per gallon" and you can use it for LEDS, too. It equals to about 75 Lumen per gallon for low light, ±150 LPG for medium light and ±225+ for high light.
Using my new calculation (1050/10), you can see the 1050 Lumen LED would work very well in a 10 gallon tank.

 

[fishorama]

This is just part of the reason I don't have LEDs yet, it's very confusing! Then there's the quality of the LEDs, reflectors, colors (fresh vs salty but there's more to it), the layout of them over the tank (the spread of individual LEDs in the fixture), the width of the fixture, tank depth & width. Raising the lamps up increases the spread but also the penetration is diminished somewhat.

I've been told to ask the manufacturer or just use X brand LEDs &/or raise it as needed, DIY my own, etc...& spend somewhere between $50 + $500!!

dougall, do you have an opinion on Riptide's lights & what "he" might be able to grow with them? Would another of the same inexpensive LED fixture get it up to "low/medium" plants lighting over a standard 75g? Might it be "blindingly bright" to our eyes?