Milan

From what I heard, CO2 tests are notorious for inaccurate/unreliable readings. Also, there have been lots of discussions about the accuracy of CO2 calculations based on pH/KH testing. I personally abandoned this approach too, and currently I'm pushing the CO2 to the point where fish start showing signs of stress (gasping for air), and then back off about 0.2 of pH.

Where does the ammonia come from? 1.0 ppm is very high for cycled tanks. This may be your reason why the fish are gasping for air, not CO2, and definitely the cause of your algae problems ... In established (cycled) tanks, you get ammonia only if you overstocked it, the filter is clogged (next to no flow), or you somehow killed the beneficial bacteria (ie changed or washed all filter media at once)...

The purpose of filters in planted tanks is firstly to provide home for beneficial bacteria colonies in sufficient manner (biological-BioMax or similar), secondly to "catch" any debris (mechanical-foam), and thirdly to do a cleanup of medications (occasional use only) after potential treatments (active carbon). Powerheads do not satisfy all three, and actually are not meant to be filtration devices in any medium to larger volume tanks, as your is. You may use it as an addition to your filter for CO2 dispersion, or water movement. A rule of thumb for selecting filter for planted tanks is it's flow. It needs to be 4 to 5 times your tank volume per hour.

I think it's hard to generalize all CF's and NF's. By looking at Sylvania site you will find that their CF's are rated at 10000hrs, while T5-12's are in the 7500-20000hrs range. Is this a case with other manufacturers, I don't know ... In other words, there is Maybach and there is Hyndai. Both of them are cars, but ....

Garhan, this has been going thru my mind as well. I would assume this method would apply to a high CEC substrate. But on the other hand, does the CEC (cation exchange capacity) apply only to cations (as per name) or any nutrient? I know K is a cation, but my chemistry knowledge does not go further than that. Any thoughts on this?

I've heard of people using play sand as substrate without problems. However, before venturing into something I'm not sure it works well, I would do a jar test on it before putting it into the tank.

Jobe sticks to my knowledge have a small percentage of N in the form of urea, so I would assume you would have to bury them well into the substrate to avoid leaching into the water column. Never used them myself, but would be interested to know if anyone has encountered any problems with this? Secondly, does anyone know how to make your own substrate ferts (slow release)out of KNO3, KH2PO4, K2SO4 ... Perhaps mixing them dry with some clay or something else ...?

I use SAPS topped with a layer of gravel. Plants are doing very well. Speaking of substrates, here is a link with some useful information (analysis) on various types of them. http://home.infinet.net/teban/jamie.htm EDIT: Sorry, forgot to mention a layer of Pure Lateritte at the bottom.

Most of the potted plants on our market come from Tropica. Here is an article on how to deal with their products upon arrival: http://www.tropica.dk/article.asp?type=aquaristic&id=227

You know what Garhan .. I've been always wondering where do those guys with beautiful tanks get their plants from ... Can't be from LFS regular stock. Look at our stores. Selection is scarce, and often neglected, quality wise. You can't trade across the border, so where is the solution ...? By reading an article on APC, I have come to a conclusion that if you are in a need for specific species of plant, the only way is to place a custom order with whoever deals with major producers. Here in Canada we are lucky that we have Tropica represented (no such luck in US, because of USDA regulations). I have found out that it is possible to place a special order with Tropica distributors I mentioned before, but the only obstacle I can foresee is their ability (say willingness) to notify you of the arrival in timely fashion. I would be very interested if someone have any experiences in such trade. Please, come forward with advice ...

Tropica carries Tonina fluviatilis. Any of their plants you can order through their distributors in Canada, which are Big Als and Pisces ... to my knowledge.

Magicide, I'm just curious, if you have any update on your PO4 issue?

Jvision, I can see your point, but there is no way he can amount such a concetration of PO4 by mere N and/or K limitation, and whitout adding it. It has to be coming from a piece of hardscape ...

Can't really see it from the picture, but how you described it sounds like a K deficiency. Older growth is affected, while new leaves are OK, right?

As far as I know lead is extremely inert in contact with water. Back in old days house plumbing (the name comes from Pb=Plumbum=lead) was made all of lead pipes ...

The problem with "all inclusive" Geo-System is that you are dependant on plants/fish stock of a local fish store. They give you whatever they decide to, matching the Hagen's specs. Is it in a good shape or not, they don't care ...

If you are into planted tanks, the most used test kits are: NO3 PO4 pH (low range, if you are adding CO2) KH/GH "Master Test Kit", the one for $49.99, if I remember correctly, has only NO3 and pH test kits from the above list.

Seems like this is not going to be an easy one ... I would assume both pieces of bogwood are genuine from lfs too ... Well, I think the last resort is to take your hardscape, piece by piece into a bucket with clean water and soak it in there for 24 hrs. Take PO4 readings before and after. Hopefully this reveals the culprit ... The spike should be significant (say >5.0) ...

Something in your tank is leaching phosphates badly, and that is affecting your KH as well ... It can't be just a bad test kit. What is your substrate? ECO Complete had some similar issues in the past ...

Those four pebbles ... where did you get them from ?

Nutrafin fert is definitely not the culprit ... That's the red label one (Iron Enriched) which does not have any P. From how you described feeding, I would rule that one out too ... It has to be something else, either your substrate, or rock, bogwood, ... Hmmm ... do you by any chance have any tab ferts embedded in your substrate? Your image didn't work for me. It doesn't show. ... You can use flash. It shows hardscape better, but take a shot slightly from an angle to avoid reflection ... EDIT: OK, it's working now ... Good enough ...

OK, so 12 is # of drops. That makes your KH=6.7, which is in order. Now we can move to your tank... Are there any stuff that you are adding to the water, besides tap water conditioner and fertilizers? Something like pH adjusters, acid buffers .... or anything else? Also, what are you using for substrate? EDIT: I can see you have a digital camera handy ... Could you please take a frontal shot of your tank showing all your hardscape ... Helps thinking ...

How did you come up with 12 now? 15 drops is 8.4 ... or you are saying your tap KH is higher than your tank? Could you please try to do a PO4 test on your tap water as well?

Unless he is on well water, and here parameters may greatly differ... Although remote, it's a possibility. So, let's eliminate that one first.

Magicide, what is your tap water KH and pH? If you calculate the CO2 level based on these two readings, it should be somewhere in the 3-5 ppm range. If higher, you have a tap water issue, in other words presence of another buffer, most likely a phosphate one. If it is in the above range, then we should look in your tank. Your PO4 level is most likely related to the KH issue, but let's do one step at the time ...