- 7 Sep 2008
- Flintshire, North Wales
ceg4048 said:Hi Stu,
Yes, lowering light is always a good idea when fighting algae. This is because light is one of the fundamental causes of algae. I'll repeat that HC, glosso and all the other carpet plants are not necessarily high light plants, they are high CO2 plants. Given the proper levels of CO2, these plants simply grow faster with high lighting, but they really do not "need" massive lighting. Generally, if you have enough light to grow algae then you probably have enough to grow HC. For example, has it registered in your mind yet that the moss, which is much closer to the light has more algal growth than some of the carpet plants? I would estimate roughly that the light energy being received at the surface of the Fissidens leaf location is about 10X higher than at the substrate level where the P. helferi is. That means the Fissidens needs 10X as much CO2 (roughly speaking.)
100 watts T5 with reflectors is a lot of light for a 30 gallon tank. Your CO2 and or flow distribution will need to be flawless to avoid trouble. So really, lighting, in a way, is the root of all evil. High lighting drives the plants to grow faster but if the nutrients and CO2 levels cannot support that growth rate then the the plants stumble, leaving them vulnerable to algal attacks.
If it is indeed determined that the higher injection rate is negatively impacting the shrimp then the only alternatives will be to have lower lighting, and/or have higher flow, and/or to use more Excel. Lower lighting lowers the CO2 uptake demand. Higher flow increases the CO2 distribution and of course, higher Excel dosing increases the available CO2 without raising the water column CO2 levels.
cheers clive, all very well explained as usual. I had realised about the moss getting the algae quicker and ive been spraying the easy carbo on that to try and help it out. Ive dropped down to 3 lights for now and the co2 is still up, drop checker is limeade green. Ive still not got around to buying an extended spraybar so thats still to do but there's still tons of flow dropping down the front of the glass and onto the carpet.
The luminaire isnt going in yet as its an xmas pressie from the wife. Ill probably try and blank one light out when it first goes on but I thought id read on here that the t5's got better penetration into the tank as the Rio is 45cm high? That plus it will be so much easier to do maintenance on the tank without a hood!