how does hight water temp affect the need for ferts

It increases nutrient demand, CO2 demand and growth rates, going from say 18C to 28C should effectively double most metabolic rates, plants included.

I run a discus tank at 82-84, this is fine for any south american fish including breeding, you might get a bit better results if you are into breeding only, if you push it to 86-88F. But....for planted tanks and nice fish, 82-84 F is fine.

EI's temp was set at 81F.

I think your issue is 100% CO2 related, that's not Ca++ issue. That's classic CO2 deficiency. Some tanks with lower light, lower biomass, higher fish loads, sediment ferts etc, 5ppm 2-3x a week is plenty, some non CO2 tanks, no NO3 dose is required for months...................depends on your set up.

If you have CO2, and are not adding quite enough, adding non limiting ferts, makes the slight CO2 issue, worse.

But, now you know the root of the issue, CO2, not nutrients(EI just made nutrients independent).

You can very slowly adjust the CO2, like O2, warmer water holds less dissolved gas, same is true for all gases, CO2 included.

Make sure there's enough current, some slight water surface movement is good, you will lose a little CO2, but gain a lot of O2(for fish), and you can simply add a bit more CO2 to account for that. This way you can add plenty of O2 and CO2.

No stress to the fish and plants grow well.
Also, lower light = less CO2 demand, so dosing and CO2 targeting is easier.
Also, discus will look better with lower light.

At 0.5w/ t5, this is a fair amount of light still, try 8 hours of light, consider raising the light up some to reduce intensity etc and go with 10 hours of light, or if you can stagger the light bulbs so that they are mostly at .25 to .3 w/l, then a noon time burst for 0.5w/l for 2 hours etc.

Any of those will help.

But the issues sound very much like CO2 in every way.
FYI, I've never been able to see or induce Ca++ deficiency in an aquatic plant tank to date, my GH's are 2-3 at most. So they are low to begin with, unl;ess you use RO and do not add any Ca++ sources, it's not likely.

Co2?

Most certainly.
See the new EI post I just did for the logic, I use a Ca++/K+ example.



Regards,
Tom Barr

 

Plants do not need to move it around, they are surrounded by Ca++ in the water, they take up via the leaves in most aquatic species, along with K+.

CO2 is the source of carbon in plants, of which 50% is their dry weight in Carbon.........so since new growth is where the most carbon is required.........that's what is most affected.

They do not do hydroponic deficiency studies for CO2, because those are terrestrial plants They are never CO2 limited.

As plants grow, they keep demanding more CO2, and as biomass increases, they keep demanding even more CO2, NO3 etc.

So yes, the temp seems to make a difference for your tank.
NO3 will be used up faster, what is your dosing routine for KNO3, KH2PO4, water changes % and frequency?, traces etc?

I add about 10ppm of NO3, via KNO3 3x a week under high light and warm temps(82F).

With a high fish load also, you might need less KNO3.
the NH4 from fish waste might be part of it also. Try large % water changes 2x week perhaps and see how that improves things. You might add a bit of K2SO4 also.

You can easily add CaSO4 to see if it's a Ca++ issue, but that will do no good, you are welcomed to try it however to prove it to yourself.

As plants start taking up more and more nutrients, they will demand more CO2, CO2 is a lot more tricky to dial in right and test than most assume.

I would suggest increasing the flow and the water surface movement in the larger tank. This way you can add more CO2 without harming the fish and only add CO2 during the day only, never at night. With discus, we have gone to 45ppm, much more than this is bad however. That was using a special partial pressure gas dissolved meter, so the ppm's are accurate to less than 1ppm.

You should not need, require more than about 30-35ppm.
The fish will turn darker if they are stressed.

You need some good O2 also, so this will counter the high CO2.

So work on that some, this should help the/any algae issues later on also.

Regards,.
Tom Barr

 

Holes in leaves is also a CO2 issue, plants can and do translocate carbn from older leaves to new ones. This is common in Hygro and Sword plants particularly, even at 30-50ppm of K+. So K+ is very easy to rule out.

You have a lot of fast gowing species of plants there.

I would work on a CO2 diffuser method perhaps and getting more flow through the tank. Maybe even adding another filter/canister and running a spay bar along the back lower wall and turn the spray bar in the picture to make a slight ripple, but not break the surface of the tank.

This will help the fish, process the food waste better, keep tank cleaner etc, you will lose a little CO2, but that can be turned up a little.

I have the same plants and no issues. So as far as light, CO2 and nutrients, seems like it can only be a CO2 issue. Also, does this occur more around the CO2 reactor or farther away?

Also, with higher fish lads, 2x a week might work better, say 40% and dose thereafter. The other thing is if the plants respond better to that water change routine, it's more than likely it's a CO2 issue. So you can check that.

You better mow that Gloss, I do not allow mine to pile up, otherwise it becomes too intense and goes wild
You can mow it little by little once every2-3 weeks, or mow drastically every few months.


Regards,
Tom Barr

 

Yes, then it is the CO2 with that species(P stellata).I've seen that before independent of nutrient or fish loading. I had done the same nutrient dosing for years and upped the CO2. I can change the CO2 and induce the stunted tips also.

It was also random, but overall, all the plants became progressively smaller in diameter, and the stems also reduced in diameter- this is to conserve Carbon, while the other P stellata plants just entirely stopped growing/stunted.

With good CO2, theplants get massive and grow without any issues.

This strongly suggest some CO2 related issues.
More water movement, more CO2, and better O2, might help, try adding activated Carbon etc if the issues does not resolve etc.

I think you can adjust a few things here and get the results, or reduce the light a little also.

Do not rely on Watts/l etc so much, the plants might get a little bit more than you think they are.


Regards,
Tom Barr