Wet/Dry Filters

[Beasts]

I'm hoping to find people with experience using a wet/dry filter on a planted aquarium. My 410 gallon aquarium currently has one and I am attempting to use it in a way to best encourage plant growth. One problem is avoiding CO2 loss. Another is trying to keep nitrate levels up. On the up side, there is very little surface disturbance in the aquarium and oxygen levels are quite high. Currently my pH varies between 7.0 and 7.2 using a CO2 injection system with an Aquamedic CO2 Reactor 1000. My lighting system consists of 864 watts of T5s in 2 four foot Tek Light fixtures. The flow rate of the filtration system is something over 2500 gph. kH is 3 to 4. GH is about 13. The fish are quite healthy.
I would appreciate hearing from anyone with any helpful comments on their successes or failures with this type of filter. Has anyone made any alterations to their system to maximize CO2 retention? What sort of nitrogen additions have you used?
Each time I try to use all of my lights I end up with green water. Most recently I was running all of the lights for 4 hours on, 2 hours off and 6 hours on. I have been experimenting with Greg Watson ferts.
I can provide additional information if necessary. I am in need of some fresh ideas. More input!
Beasts

[phanmc]

Haven't used a wet/dry filter for a high light planted tank but there are others that have and the recommendation is to seal the wet/dry unit so no gas can escape it. If you seal the unit, the gas will have nowhere to go and will eventually dissipate back into the water, so no CO2 is lost.

With a tank that large, I wouldn't consider using anything else but dry ferts from Greg. Make sure you're dosing your macros and micros (KH2PO4, KNO3, and CSM+B should be enough for most cases).

Might want to reduce the light if your fixture has individual bulb control. 864w is a whole lot of light, even for a 410g tank. Knocking off a 100w might make things more manageable. Is your tank heavily planted?

[Rex Grigg]

Seal the wet/dry, minimize all water splashing and turbulence in the wet/dry that you can.

You also need a MUCH better reactor. An Aquamedic 1000 is not up to handling a tank that size with a wet/dry.

Your CO2 levels are somewhere between 5.7-12 ppm. You really want 30 ppm.

I too would cut down on the light. You actually have a very high light tank for a tank that size.

What is your load of fast growing plants like? How long has the tank been set up?

To add nitrogen you need KNO3. A LOT of KNO3. You would need to add 3 tablespoons to get to 20 ppm of nitrates. There are 4 tablespoons in a 1/4 cup just so you know.

[Beasts]

A few thoughts;
The filter side of my sump is sealed so well that the water level in the filter side is approximately 7" lower than the open side. The gas pressure gets so high that it drives the level low enough on the filter side that gas escapes under the divider between the two sides. I can't seal the pump intake side because of the heater cord, pH sensor wire, Auto Topoff connections and submersible pump connections.
I can turn on half of each light fixture separately from the other half. I will try removing bulbs and see what happens in an effort to eliminate just 100 watts.
The information available in this pursuit/hobby is sketchy, fragmentary, frequently inaccurate and contradictory! I have been told that fluorescent lights would have trouble illuminating the depths of a 30" deep aquarium and, therefore, wasn't concerned about having too much wattage. Amano uses anywhere from less than one to more than two watts per gallon on his large aquariums - and he never says what type of lights or reflectors he is using! The most recent "expert" I spoke to felt that I might solve my problem by introducing the 2 hour dark period midday but did not suggest lowering the wattage.
The fertilization regimens I have researched, including yours Rex if I remember correctly, depend on frequent large water changes. Is there no way to follow a compromise approach somewhere between Walstad and Amano? I would like to do continuous water changes with light, CO2 and fertilizers balanced to maintain healthy but not necessarily constantly pearling plants. I have 4 smaller aquariums that are low tech with low wattage fluorescents and no CO2 injection that support plants which are healthy but grow very slowly. Is there no middle road here?
The Aquamedic 1000 was sold to me as being quite capable of handling my aquarium with the wet/dry filter! But you're right Rex, it doesn't keep up during the lighted period. Have you any specific suggestions?
The aquarium has been set up for about 7 months. The entire substrate is planted except where there is driftwood or rocks - less than 15%. My fast growing plants include Rotala, Ludwigia, Vallisneria and Hygrophila all of which are growing reasonably well. The Vallisneria is, of course, a weed and is the only species which pearls consistently. The Echinodorus are growing very slowly (high light) and the Cryptocorynes (mostly low light) are hardly growing at all.
Listening to Diana Walstad I have been feeding my fish twice a day, in part to add to the nutrients available to the plants. I would prefer using food and fish waste as natural fertilizers as opposed to manufactured inputs to the extent possible. There are approximately 80 fish from Corydoras to altum angels, bala sharks and congo tetras among others. I am trying to figure out how this bioload would affect my fertilizer dosing. I can provide a complete list of the fish if that would be helpful.
I'm ready for Round 2. Thanks for your input.
Beasts

[Rex Grigg]

While I have not used the reactor I will link you to I know someone who has used one in a sump. You will most likely need two of them for your tank.

http://aquatic-store.com/index.html?target=p_101.html&lang=en-us

The "siesta period" is popular among some people but has never really been proven to work.

I show the EI method because it's easy to use and works. If you want to use test kits then just keep the nitrates around 10-20 ppm and the phosphates 10% of the nitrate levels. Dose traces a couple times a week and you will be good to go.

Unless you cram the tank with highly unhealthy levels of fish the fish waste alone will not work with a high light CO2 injected tank. Note that Walstad method doesn't use high light, or CO2 and relies on soil based substrates to a large part.

If your fish add 10 ppm of nitrates and 1 ppm of phosphates then perhaps all you need to add is traces and some potassium. But the problem with the fish adding those levels of macros is that they also add huge amounts of other dissolved organic compounds that can only be removed with water changes.