Problems with Plant Growth in NEW setup

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.

 

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