Snail eating tankmates for Agassizii

[gerald]

I totally agree with that. High-tech planted tanks typically use cheap common hardy fish that can do okay swimming in fertilizer solution with elevated CO2. Folks on this forum keeping soft-water dwarf cichlids, blackwater gouramis and tetras, etc need to focus more on the fish's water quality needs and keep plants that tolerate low mineral content, low nutrients, and low light.

My plants actually have a nitrate deficiency, and I need to dose it, but alas I haven't bought it yet because to me my fishes health is more important than my plants having the perfect color. My logic has been the plants are doing well without dosing nitrate although not pristine. I like my plants but I believe my fish would be happier in such low nitrate levels so I choose not to dose. What is your opinion on this darrel?

Hardness (GH) is a measure of divalent (+2 charge) cations, mainly calcium and magnesium. It has nothing to do with pH or buffering.
Alkalinity (KH) is a measure of acid-buffering capacity, mainly bicarbonate (HCO3-) and carbonate (CO3=). Alaklinity does not affect hardness (and I sure wish people would stop using the term "carbonate hardness") !!! In natural water, limestone is the most common source of both GH and KH, so they're often present in roughly similar quantities. And if you heat water, some of the GH and KH will precipitate out of solution as CaCO3 and MgCO3, thus the term "temporary hardness" - that's relevant to industrial boilers but has little relevance to fish keeping. If your buffer additive is raising GH, then it probably contains some Ca or Mg. Baking soda (sodium bicarbonate) will only raise KH and does not affect GH. Epsom salt (magnesium sulfate) will only raise GH and does not affect KH.

I thought gh not only calculates things that raise ph but also things that lower such as salts. I thought kh is the one that matters and what decides if water is soft or hard. I use ro water and the only reason I have a 5 is because I add a ph 6.5 buffer. Nothing else is added and before hand they are both below 1

 

[dw1305]

Hi all,
"What is your opinion on this darrel? I have not read through your link yet because I'm at work and only firing out a quick reply, but I will after work."

I like low levels of nutrients, my aim is to use plants to maintain very high quality water. Actively growing plants are the single factor that has the greatest effect on water quality, so I only add nutrients if active growth has stopped.

The idea behind EI (Estimative Index) is that CO2 and mineral nutrients are never limiting, and that you raise the levels of these to match the incident light (PAR). It isn't a route I ever envisage going down. I think one thing aquascapers have shown is that NO3- itself isn't particularly toxic, and that you can add it via KNO3 etc without any problem. If you aren't adding fertilisers, high NO3 levels are the "smoking gun" of previously elevated levels of NO2 and NH3/NH4+.

The idea behind the "Duckweed Index" was that CO2 and nutrients are always limiting, and you only add nutrients if active growth ceases. CO2 only arrives in the tank via diffusion, and it differs from the Walstad method in that I like a large gas exchange surface via a trickle filter etc. I just adjust the plant mass to the light I have, more light means a larger plant mass.

Plants need more of the macro-nutrients, N: P :K than they do of any of the other nutrients and it is these nutrients that are likely to be in short supply. Realistically plants actually need about x10 more N and K than they do P, so adding KNO3 is a good place to start.

cheers Darrel

 

[Mol_PMB]

I think one thing aquascapers have shown is that NO3- itself isn't particularly toxic, and that you can add it via KNO3 etc without any problem. If you aren't adding fertilisers, high NO3 levels are the "smoking gun" of previously elevated levels of NO2 and NH3/NH4+.

This is a very interesting thread - thanks.

With an effective biological filter, high NO3 levels aren't necessarily linked to high levels of ammonia/nitrite toxins, they could just be indicative of a large fish waste buildup over time which has been effectively processed by the bacteria. However, there may well be other harmful chemicals in that fish waste that are not dealt with by the nitrogen cycle bacteria. High NO3 levels are therefore a good 'flag' that you should dilute some of these with a water-change.

I too have tanks which run with low TDS, near-zero nitrates and floating plants, but IMHO it's still necessary to do regular water changes.

Cheers,
Paul

 

[dw1305]

Hi all,
"high NO3 levels aren't necessarily linked to high levels of ammonia/nitrite toxins, they could just be indicative of a large fish waste buildup over time which has been effectively processed by the bacteria."

That is right, they don't necessarily indicate a pollution event, it could be lack of water changes or just a high fish load, where levels have built up as the end result of the action of the nitrifying bacteria acting upon the ammonia that is continually diffusing from fish and invertebrates. A problem for a lot of people is that their tap water contains ~30 ppm NO3, meaning that dilution with tap water doesn't really help.

Personally I've always used rain-water, I only have planted tanks and I'm a fanatical water changer, 10% a day in all tanks, and more in smaller ones.

If you continually have high NO3 levels you need to address it. Assuming you don't harvest your fish, you can only remove the NO3 in 3 ways:

• Conversion to plant material and removal of the plant biomass.
  
• Anaerobic degassing.
  
• Dilution with "cleaner" water.

Anaerobic degassing via a plenum or denitrifying coil is possible, but not easy, and having a canister filter where both aerobic and anaerobic processes occur (which is apparently a reason for buying some porous filter media) is such a poor idea I'm not even going to go there.

Biological filtration is really all about oxygen, you can forget nearly every thing else. As long as the oxygen supply exceeds the BOD things are fine. Plants lower BOD and supply oxygen, why look any further?

cheers Darrel