Sorry to hear of your woes Rodders. Hopefully you will have more success next time around.......
On the NP dosing issue - Obviously there is some difference of opinion here but I'd just like to say a few words from my perspective as I have experience from both sides of the fence.
I have previously run my 125L (33G) using the Dennerle system; Trocal lighting, Deponit substrate, heater cable, A1, S7, TR7, PFG7, E15 and V30 ferts - all by the book (I have the book too). I had great success with this for several months as you can see by the first photo in my journal.
However, after a few months some plants were displaying various nutrient deficiency symptoms and algae. After some research I discovered that these defs. were nitrogen and phosphorous related. I was confused as I assumed that my undetectable PO4 (I used RowaPhos) and very low NO3 were ideal. I read the Sears-Conlin/PMDD paper that stated that the best way to control algae was to use PO4 as the limiting growth factor. All main UK sources backed this up – and still do so today, you only have to read PFK’s series of planted articles by Jeff Walmsley.
It wasn’t until I read, from various overseas sources, that dosing KNO3 and KH2PO4 were common practice in high-growth systems. So gradually I implemented this new philosophy and started dosing KNO3. Instantly I saw positive results; in particular my Hygrophila polysperma burst into life again. I still used RowaPhos though as I was very wary about PO4 and its apparent algae triggering. I then learnt that the constant green spot algae (GSA) issues that I was experiencing were due to low PO4. So I removed the RowaPhos and dosed KH2PO4, and guess what? Away with the GSA and further improved growth.
Now I have done away with my Dennerle lighting and ferts entirely. I now use cheap full-spectrum tubes (£4.89 each compared to £13) and dry chemicals (KNO3, KH2PO4, K2SO4, MgSO4 and trace mix) – all costing a tiny fraction of “off-the-shelf” equivalents. The results speak for themselves if you read through my journal.
I think it is important to re-iterate that dosing N and P is not for everyone. Even those with apparently high lighting and growth rates can run healthy tanks without dosing N and P. PFK’s Jeff Walmsley is a good example. His photos certainly indicate that he has no algae issues but it is worth thinking about his methods. He uses a soil-based substrate that in itself will provide massive quantities of N and P. He also has very soft (mostly rain) water and is planted with stem plants that require minimal macros. His MV lighting maybe high in output wattage-wise but it is very inefficient, so the nutrient uptake is not sufficient to require dosing the water column with additional N and P. His fish and their food/waste will provide enough. The fact that he performs minimal water changes will ensure that sufficient allelopathy takes place to limit algae too I would guess.
What we are seeing are two very different ways in running a planted tank. Both work, it is up to the individual to choose what most suits them. I personally prefer to see rapid growth, loads of pearling etc. I don’t mind the weekly 50% water changes and intensive fert. dosing regime. I do not have any algae issues though (in fact my only downfall has been BGA due to low NO3) and I can grow any plant I wish. A tank without dosing N and P will be limited by plant species.
Those running lower lighting (inefficient MV for example) and limited plant choice may have success with not dosing N and P, particularly if they have a decent substrate.
In conclusion the dosing of N and P is absolutely necessary for tanks that have such high growth rates that determine that without this dosing, the NO3 and PO4 levels would reach undetectable levels, thus leading to defs. and algae. For me there is no arguing on this as I have experienced such conditions.
Typically tanks with over 2 WPG fluorescent (reflectors), CO2 injection, large plant bio-mass and low animal bio-load will require additional N and P dosing.
Steve711 – Your lighting levels (approx 4 WPG) are not necessarily high light due MV’s inefficiency. The fact that you have such success with lace plant indicates to me that the opposite may be true, as this and most Aponogeton sp. prefer lower-moderate lighting levels.
It is true that some EI users suffer from algae but this is more than likely due to issues with lighting, CO2, low plant bio-mass, lack of water changes or a combination, thus the dosing of N and P further exacerbates an already problematic system . As EI becomes more widely recognised some are “jumping on the bandwagon” and using it for inappropriate circumstances. I did mention this potential problem a while back and my initial comments in zig’s article should help prevent this.
I understand your unwillingness to take the EI route. It does seem to go against common schools of thought and requires a certain leap of faith. I’m sure you’ll do fine without dosing, as I did, but if or when you do experience problems you may find the solution in N and P – so please don’t rule it out entirely.
Regards
George
