A Familiar Problem?

[Terry]

I am looking for some ideas.  My problem - plants do not grow (except they do seem to make pretty good root systems. but that is about it).  But I am now starting to get hair algae.  My tank - 30 gal, with two T5 HO bulbs, 67K and 10K.   8 hour light period with a mid day three hour lights out period.  Very low nitrates (10 ppm or less), do not test for phosphates but suspect low as my fish load is small and I do not feed heavily.  Temp at 78.  City of Ottawa tap water, no PH tests or changes.  No ammonia or nitrites (these I do test for).  Gravel is coarse, which might be one of my problems except for the root growth.


I have tried hygophilia (a couple of types), Crpts, sagitaria, amazon swords, all the usual suspects.

So, any ideas? 

[fischkopp]

Low nitrates and phosphates are good for reef and fish only tanks, but not so for planted tanks. Plants do require these nutrients for growth, and if an abundance of plants is present it needs to be supplemented. Maybe start out adding some basic NPK fertilizer at 1/4 to 1/2 the dose recommended on the label. Maybe you can even find a product that contains a little iron as well.

I also notice that you do not list any existence of CO2 supplements. With the light intensity you are running I would recommend to have some source of CO2 addition, and my suspicion is that low CO2 is another reason why the plants don't grow, but the algae does. You can add either with the DIY sugar/east method or with Seachem Excel. Personally, I would do DIY as this gives best result, but Excel is more convenient. Another opting is pressurized CO2, but the initial setup cost here is quite high.

Good luck!

[daworldisblack]

+1 on what Fischkopp said. Ferts are necessary for planted tanks and especially so with the high light you have over this tank. The lighting available makes the plants want to grow but they seem to be unable to, due to a lack of the necessary nutrients - ferts and CO2. Supplementing each can be done either by dosing dry ferts (available at hydrophonics stores usually) or you can start off with readily available ferts (Seachem, API are some brands available in stores).

As for co2, gas is definitely better then the liquid alternative (Seachem Excel). For gas, you have the option of DIY co2 using the various concoctions (google it) out there that basically is a reaction to produce c02 which you diffuse into the water column by a diffusion method. The different recipies help with stabilizing co2 production levels mainly it seems. I never stuck with it too long and its impractical for larger tanks but at 30Gallons you can give it a try and see how the plants respond. The inevitable path would be pressurized systems as it gets impractical in the long run if you stick to DIY - cost of materials over the long run, time spent, etc. With pressurized systems, you just have the initial cost of set up but its set-up-and-forget-about-it sorta deal. These days they have regulators for paintball tanks to regular co2 tanks. For a larger tank like your's it could be economical to set up a larger co2 tank and refill as needed at a fraction of the initial set-up price. This in the long run is more economical then liquid ferts and DIY both in terms of time, money, and hassle.

Of course if your priority lies in the fish rather then the plants, then you can choose not to go into any of the things mentioned above but you'd have to limit your lighting so its a low-light tank and your plant selection is also not as varied in terms of what you can keep. Most species will do fine but grow way slower but its not necessarily a bad thing - its seen as 'low-maintainence'.

So in essence, either address the issue of insufficient nutrients or cut back on lighting. Hope that helps.

[Terry]

Well, thanks to both of you.  That makes sense - I have had a low light tank previously for a long time (one 24 inch T8 on the tank)but I did not register that my current lighting would be "high", I thought just better.  Some plants did very will under the low light, but I got ambitious.  So I will try dosing nutrients and may fire up my CO2 yeast system.  If all else fails, maybe I will go back to low light.

Thanks again

[exv152]

Like Rah said, I'd recommend one of two things; 1) either decrease the light or 2) add ferts & co2. Otherwise just adding ferts and leaving the co2 situation the way it is will not help much.