Hi

I'm relatively new to the hobby of keeping aquatic plants in an aquarium.
I have a 120L/30 Gallon tank, with 3x18W T8 + 1x24W T5 lighting or about 2.5W/gallon. CO2 is provided by yeast fermentation, the Hagen Nutrafin system but my own "brew" that gives more CO2. I try to keep the CO2 stable by starting a new "brew" every 5-7 days. CO2 levels seem to be OK judged by a Cal Aqua Labs drop checker.
EI is the method I use to provide macro and micro nutrients. I'm using CMS+B and KNO3,KH2P04.
Substrate is just gravel, probably inert when it comes to nutrients.

I mainly have fast growing plants in my tank: Hygrophila polysperma, Limnophila sessiliflora , Vallisneria americana. All grow quite fast. Limnophila sessiliflora will overtake the tank completely in about 2 weeks if I don't prune it and remove new plants at each water change.

But I've always had problems with the Hygrophila polysperma. It was my first plant and I chose it as I read it was supposed to be one of the easiest plants to keep. The leaves will often be deformed or wrinkled and sometimes holes. Shortly after a leave has formed it will get pinholes that start to grow. In a few days the leave will curl. Sometimes the leaves will have white vains.

The water here is very soft. Probably abt 1dGH and 2-3dKH. I add GH booster to get GH up to about 5dGH as I've read that lack of Mg/Ca can cause pinholes.


I've attached images of the H.Polysperma showing what I describe. Any ideas what could be causing this?

I also have this plant, and it will often be the first to show symptoms of a deficiency since it's such a fast grower. The only times I've ever had serious problems have been when co2 levels have been out of whack/fluctuating. Since you are dosing EI, I would say that co2 is your problem. Do you have 4KH water in your drop checker? Does the color fluctuate? How many bottles of co2 brew do you have? What are you using for a reactor? I have the same size tank as you and I have two 2L bottles running, one of which has to be changed weekly to keep co2 steady and I also have to add an additional 1 tsp of yeast to the bottle I don't change. The output runs into an internal filter which chops it up into tiny microbubbles and dissolves most of it. In this way I keep my drop checker at a yellowish green.

The two times I've had serious issues with my hygro was:
1. I stopped co2 injection - got pinholes that enlarged slowly until the whole leaf fell off. I was pulling out a net worth of leaves every day for a month until I started co2 again, problem went away within a couple of days.
2. CO2 was fluctuating due to poor maintenance - this time, new growth looked like pieces were sort of missing, and the leaves were a bit deformed like yours, and algae started growing on them which normally didn't happen. Kept co2 stable at greenish yellow for a week, after that time new growth was looking normal again.

I also only have 2wpg with poor reflectors.

Yes I have 4KH water, at least I have what Cal Aqua Labs supply with their drop checker. I only have a single 1/2L bottle for the brew. The reactor is a "slide/ladder" that the bubbles travel along for quite some time. One can see them dissolve and getting smaller. I guess 80-90% of each bubble is being dissolved. I've been thinking if it could be lack of CO2 but the color of the drop checker is stable and the "correct" color.

This video shows a reactor like I'm using.

Guess the next step is to add more CO2 and see what happens. It is interesting to hear how much CO2 you are using compared to me.

Where is the drop checker in relation to the co2 ladder? If it’s near the ladder then you’re not getting a very good indication of overall co2 saturation.

Good point.

It is as far as possible from the ladder, opposite end of the tank. That should not be a problem.

In that case I'm sure it's a co2 issue. I can't imagine trying to maintain sufficient co2 levels in that sized tank with only one bottle and 1/2 liter at that. It's just impossible. Even on a 10g I had to use 1-2L bottle. One 1/2 L bottle would only be sufficient for maybe a 5g tank, if that. Even when I totally restart both bottles with fresh yeast and sugar, and there are literally co2 microbubbles flying all over the place continuously to the point where I can hear them over the TV, my drop checker never gets above greenish yellow. What you should do is make up some new 4KH solution using distilled or RO water and baking soda, and add bromythmol blue to it. This will give you an accurate reading. I have no doubt that you are not getting sufficient co2 with your setup.

The mix I use is 2c sugar, 1 tsp yeast (bloomed before putting it in the bottle), fill the bottle to within 3" of the mouth. After one week, I add 1 tsp of additional bloomed yeast. After two weeks, I change out the whole bottle. I stagger them so that every week I'm adding 1 tsp of yeast to one, and changing the other. I also keep a 25 watt incandescent bulb in a desk lamp shining on the bottles 24/7 to keep the bottles heated hotter than room temperature. This maintains my drop checker in the green range. Any hint of blue, and I know something went wrong and change out both bottles immediately.

Do you have a hob filter or a canister? In either case, if you run your co2 output line to the intake of the filter so that it sucks up and at least partially dissolves the bubbles, you will probably do better with dissolving and circulating your co2.

I used to have that same ladder set up for one of the 10 gallon tanks. You should try another method to diffuse your CO2. Search here for CO2 diffusion or distribution...you should find how to use a power head to diffuse the CO2 around the tank. I'm using it and growing many plants with this method. You will see a huge difference
One example: a friend of mine has a CO2 tank without a solenoid and using the ladder set up on 24 hr with no problem.. He changed the ladder for a CO2 reactor. When he changed to a reactor the next morning found his discus almost dead. Why? more CO2 distribution during the night - that he did not use to have with the ladder- and, well he bought a solenoid and a timer.

Look on the articles board for the DIY internal reactor. This evidently works to nearly 100% efficiency. But you'll still need to upgrade your bottles.

Yes I plan to build that internal reactor and add it. Might also try Excel.

It puzzles me though why I get a "correct" color on the drop checker that indicates 30ppm of CO2. I've contacted Cal Aqua and they have confirmed that the indicator solution provided is 4dKH water created from distilled water and has bromythol blue.

Yes I plan to do that. But still I can see the bubbles travelling up the ladder getting smaller and smaller and almost dissapearing before they get to the top. It must be the gas being dissolved into the water. That suggests the ladder is doing a good job of dissolving the CO2.

Lots of new things to study and learn!