Problems with Plant Growth in NEW setup


Junior Poster
Mar 13, 2007
Hi – I’m looking for some advice, as I’m not happy with my plant growth/appearance in my recently (3 months) set up 5’ circa 75 gallon freshwater aquarium. I’ve kept freshwater tropicals for about 20 years with no major problems. My most recent tank was about 40 gallons and with homemade CO2, the plant growth was pretty good, to such an extent that when I took it down to replace with the larger tank I sold loads of Anubias and Crypts to my local pet shop. I never measured PH or anything else in that tank.
So you can imagine my disappointment now after having my new tank setup with pressurised CO2 to find plants not growing very well and very anaemic looking.

In my recently set up system I wanted a greater emphasis on plant growth and have tried to be a bit more sophisticated about the equipment. The NEW tank details are as follows:
75 gallons, 18” depth of water, temperature 78 degrees, substrate- coarse sand above a layer of gravel with Red Sea Flora Root between the two layers, total substrate depth 3”.
Lighting on about 10 hours a day and is currently by 4 x 4’ tubes as follows:
Interpet Daylight 36 w
Zoo Med Flora Sun 32 w
Triton 38 w
Sun Glow 40 w.
There are no reflectors although the lights are screwed onto the lid of the tank which is painted white (although faded a bit). I am thinking about changing to Interpet T5 High Power compact system, but in the short term I could add another 4’ tube to the existing (I have the equipment). Filtration is via a Tetratec 1200 external filter.

I am using a CO2 system from LunaPet in Germany with a solenoid to give CO2 for about 12 hours a day. I have an internal reactor from the same company and bubbles through the counter are currently approx 90 -100 minute. I am getting “pearling” bubbles off plants during the latter part of the day. The PH level (metered) is between 7.2 and 7.4 hardness, Hardness measured using card test strips is around 10, but I am not totally sure on this as the colour difference on the chart between 7 and 14 is not great.

The plants are various and include Giant Vallis, Hygrophilia Polysperma, Crypts – including Balansae, Cordata, Nevii, several Bacopas. Speciman plants Echinodorus Paniculatus (?) and Apongeton Ulvaceus. The tank is populated by about 50 fish including Tetras, Rainbows, Barbs, Corys. Bristlenose Cats and a Pleco.
I am water changing every 2 weeks about 15 – 20%

The problem I have is that the plants are not growing well and not very lush/green looking. Vallis leaves are yellowish and semi transparent, the Hygrophilia leaves are falling off in large numbers and the Crpyts look anaemic and slightly shrivelled. I have green algae on the inside of the glass, which comes back within a week of cleaning.

Any HELP to resolve this issue would be much appreciated.


Junior Poster
Apr 4, 2007
Looks pretty good... I think you could lower your lighting hours to cut down on algae.
My name is Terry too!


Prolific Poster
May 18, 2007
Wirral NW england
Sounds like you are describing my set up my water is about the same as yours (Ive added peat to lower the PH)
I have no fish as yet so Im not adding any food as such for the plants save for a dose of plantamin once a week.
I look forward to seeing what the comments are

Tom Barr

Staff member
Jan 23, 2005
You have plenty of light, tritons and mix of cool whites gievs a nice color, so 2-3 tritons and a cool white(cheaper too).

You have CO2.
I'd suggest learning everything you can about CO2, how to inject it, add it, etc, and how to determine the ppm's using the pH/KH/CO2 charts etc.

As far as the rest goes, all that's left are nutrients.

We can fortunately avoid the testing part here, perhaps later, the CO2 as well, see the pH drop checker method, I think mixing that up once every 2-3 weeks will be fine with your habits.

See the thread on EI here in the articles section.
Read it, then read the light version as well.

I did the same thing many years ago, but I had any eye for the plants and got lucky. But plants do not grow merely due to I set out to figure out all things aquatic plant.

I learned there are trade offs and places you can cut corners, make the tank better for fish as well, and no testing.

Then I can focus on the hobby I like rather than monitoring, testing and micromanagement.

So.......are you adding any nutrients to the water column, Trace elements? NO3, PO4 or K+?

Tom Barr


Junior Poster
Mar 13, 2007
Hi Tom - the answer to your question is no, I've not been addiing any fertilisers. My previous tank of about 40 gallons (UK) had been set up for about 15 years, only in the last 2 years had I added a DIY Co2 - had good plant growth with 2 x 38 w tubes.
Back to the new tank I bought 3 bottles of Tropica Aquacare liquid water plant nutrition, cheap, from my LFS a month or 2 ago and perhaps should start using that. I will study and try to understand the EI - I've had a quick look at it and haven't really come to terms with it yet. Thanks for your input. Terry


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
Sacramento, CA
When you added the CO2 it, with the good lighting encouraged faster plant growth, which quickly depleted the minimal nutrients the plants had available, so they are now starved for nitrates, etc. You do need to fertilize if you use CO2 and good lighting.