CO2 and Sumps

[freshwest]

I am running a 450 l (planted) and a 300 l (bare)tank filtered by a 100 l baffled sump . I originally designed the sump as a wet / dry filter but i have removed the dry section 1. because it was cooling the water to much and 2. the high gasing of the dry section was raising my pH . My Q is will i get much benifit from a co2 system . My flow rate is not overly high and my outlets are below the surface keeping surface movement to a minimum . The water quality with this system is excellent but plant growth is slow . I dose with pmdd and have plenty of light so i have come to the conclusion co2 is the missing factor . The co2 should also help in keeping my pH down as I keep discus . Anyone out there running a sump and co2 ?

[Shilo]

I'm not to worried about C02 loss with a W/D. Currently running a DIY yeast system with a W/D filter. My readings range between 11 and 15ppm.

I actually believe that C02 loss with a W/D is an old wives tale. Sure there is a lot of out gassing when the water trickles through the filter but C02 is heavier then air and will sink to the lowest part if there isn't to much air disturbance in the system. If the C02 sinks then it will come in contact with the water that it had just out gassed from and be reabsorbed. The only way C02 will be lost to the system is if there is air turbulence in the sump which can blow the C02 away from the water. Strong water movement (waterfall effect from baffles etc) could cause this air movement but if its a quite sump then there shouldn't be much loss.

This article might interest you: http://www.hallman.org/plant/booth2.html

Pic of my W/D filter and sump below:

[freshwest]

Thanks for reply shilo . Good info in that link . Like the look of your sump what is the media in your dry section ?

[Shilo]

......what is the media in your dry section ?

What ever I could lay my hands on Probably 20% ceramic noodles, 10% pumice and 70% cut up drinking straws.

If I was to do it all again I would make it from 100% straws. The noodles can clog and are too expensive while the pumice lacks surface area and aren't that good with water flow. With the 5mm - 1cm straw sections, although they don't have as much surface area as the noodles they channel the water very well and there are no dry spots in the filter. Theres a lot more surface area with them then something like Bioballs. An added advantage is that I don't have to clean the filter at all (apart from the prefilter sponge).