This info deserves separate topic at least.
This info deserves separate topic at least.
You are correct, raises toward alkalaine. Edited to correct.Originally Posted by Floyd R Turbo
There are countless numbers of reefers that would disagree with this when combating low pH !!
No, CO2 dissolves very easily in water, much easier than Oxygen which is quite difficult to get dissolved. The reason that CO2 cannot be added to water by using an airstone is because the atmospheric concentration, at 380 ppm, is too low to make any difference. More CO2 is expelled from the agitation than enters from absorption.
The reason that CO2 dissolves so easily is that it actually changes chemically, into carbonic acid. I'm not well versed on this, I could look it up, but the gas, CO2 dissolves incredibly well in water. I found this by experiment when testing different diffusers with a 20 pound tank of CO2 in my system. A cubic foot of pure CO2 can go into the water and be completely dissolved in about 2 seconds at 15psi! Air, on the other hand, would never come close to this, it would take hours to get that much air in solution.
Not sure about the 2 second dissolving time because I was only aware of a 23 second half absorption rate, but yes Co2 is easily dissolvable as I have proved recently. The problem is that most carbonic acid is almost immediately turned into bicarbonate and carbonate ( depending on the pH ). I assume that this is less of a concern with freshwater systems as the pH is lower enabling more Carbonic acid to exist. And again Co2 it removed from the system relatively easily by aggressive aeration or turbulence. A balanced system is where as much Co2 is being dissolved as is being expelled.
I watched it happen, the CO2 going into solution, real time, quite impressive. The exact amount and pressure and temperature are estimates, but it was a bunch and real quick, visible through a one quart reactor that I had spliced into the discharge side of the pump, in front of the filter and the heater. It kind of shocked me as I was fooling around and accidently put a blast from the high pressure tank into the diffuser, whoops, and expected a big discharge of air into the tank, but the CO2 just dissolved magically away in a second or two, not one bubble into the tank. Probably shocked the fish, though.
As I progress on this rant it should be noted that none of this applies directly to salt water, I am staying strictly with fresh water. Salt water adds complexity, the physical characteristics of the water change as the H and OH ions in the water are weakly bound to the Na and Cl ions. Some of the ideas transfer a bit, but salt is a different beast. Further, I have never attempted or experimented with salt water so I have no experience to draw upon there, and that is where my strength is.
Part II -Water
The first step to a healthy aquarium is to add water daily. But if water is added, in significant quantity, daily, water will also have to be removed. Daily water changing is the most important maintenance on a closed aquatic system. If there is not an automatic mechanism to execute the water exchange, it will not be done on a daily basis by the hobbyist, period, end of story. The percentage of water to add daily will vary depending upon the aquatic system, the input water and the automatic exchange mechanism. A rough estimate is around 5% addition of water to the system daily. If this is translated to 20% to 50% per week that is certainly better than not changing the water at all but not nearly as beneficial, especially to aquatic plants, as smaller daily additions. The mecanism that I use relies on water timers to feed in charcoal filtered well water and RO’ed water in roughly a 50/50 mix. As the new water feeds in, the level in the holding tank rises and the excess drains out of an overflow. When the well water feeds in, I can see a significant increase of bubble formation by the plants, which is a result of the high level of natural CO2 contained in the well water. The effect lasts for about an hour. Other hobbyists have probably noticed a similar effect after pouring in new water to an aquarium with plants when doing a water change, unless they let the water sit overnight to remove chlorine in which case the CO2 is also gone.
After changing the water, the quality of the input water is of the next level of importance. In general untreated municipal or untreated well water cannot be used exclusively. Doing so results in brown, red and bright green algae, the bright green stuff really being cyanobacteria with the distinctively fishy smell. Most plants will not tolerate this water, for various reasons, and will gradually die. So what about RO’ed or distilled water? I’ve tried both and pure RO’ed or distilled water will quickly kill almost all plants and fish as they both need some salts.
Use a good water test kit, once, to see what kind of water that you are dealing with ‘from the tap’. As mentioned before, it is going to have elevated levels of nitrogen, measured as nitrates and nitrites. Check for phosphates, less likely. Check the iron and copper levels. My water has a fair amount of copper which is toxic to the plants but even more toxic to some algae. The iron will not be in a form that is useable by the plants. Test for hardness but all that I recommend is using a conductivity meter which simply measures the electrical conductivity of the water in microsiemens. It is measuring the ion concentration, most of which is salts. Experience shows that between 200 and 400 microsiemens is ideal. Pure RO’ed water is about 20 microsiemens. Don’t get fixated on parameters, they can fluctuate and are not absolute. I don’t pay any attention to ‘general hardness’ and ‘carbonate hardness’. Do not make large changes to the conductivity and pH, particularly the pH, it is a losing battle. Reactors, dosers, softeners etc. are all losers, stay away from them. Work with what you have. If the house has a water softener hooked up, the house water is unfit for an aquarium, period. An aquarium will run fine between 250 and 400 microsiemens with no observable differences between high and low to the fish or plants. pH ranges between 6.8 to 7.5 are great, but don’t force it with acids like phosphoric. Typically a 50/50 mix of RO/tap water will get you into this range. Again, work with what you have and make automatic water additions, the parameter changes should take days or weeks or months to develop. Water as alkaline as 8 and as hard as 600 ms is just fine for most fish and many plants, some prefer it. Filter the tap water through a charcoal cartridge to remove nitrogen, phosphates and heavy metals. The charcoal raises the pH slightly. CO2 will more than counter the charcoal pH rise, but CO2 is not mandatory for a planted tank, it just helps.
So now we have a bare aquarium with mixed RO and filtered tap water being changed daily. It will take a week for this system to stabilize, for the bacteria to colonize and for everything settle out. If we add light there will be algae. Brown, red and bright green at first but it is the light green, both stringy and crusty stuff that is preferred. If the tank can grow good light green algae, it can grow plants.
12 hours of light a day is plenty. Adjust the RO/tap mixture so that algae growth is controlled under consistent lighting. Two week glass cleaning intervals is a reasonable goal. By adjusting the automatic water changes and controlling the quality of the water, this basic aquatic system is stable, healthy and sustainable for years. A mechanical filter is of little use. It won’t do much harm, if cleaned regularly, but it doesn’t do much good. Most filters are used to provide good circulation, which is extremely important, but the mechanical filtration can be exclusively handled by a simple sponge filter cleaned weekly. Either way all of the fancy filters and reactors are mostly products of advertising campaigns. Bacterial filtration and reactors are way over rated.
TBC - Next up is gravel, heating, lighting and nutriments.
Great info, again. Why not water softeners though? I seem to recall that use of softened water was OK. I ran a planted tank for years using it.
Also IIRC the RO tap goes on the pipe after the softener, but that is irrelevant to the information you presented - just worth mentioning.
So this info is great...but I'm still waiting for the turn of the road where an algae scrubber works with a planted tank, when can we expect that? Because that is something I definitely want to hear about.
1) Reactors, dosers, softeners etc. are all losers, stay away from them.
2) If the house has a water softener hooked up, the house water is unfit for an aquarium, period.
Not sure which statement you are referring to. 1) is just a general waste of money/time. 2) is actually harmful. Whole house water softeners (most of them) work by adding salt to the water, potassium chloride, forcing out the calcium and magnesium carbonates which are considered 'hardness'. The potassium chloride is worse for aquariums than the calcium or magnesium carbonates. This is also why I recommend using a conductivity meter and disregarding all of the GH/KH stuff.
I seem to recall that use of softened water was OK. I ran a planted tank for years using it.
Aquatic systems are variable and complex, there will always be exceptions and folks that have different results. What I am outlining is something that will work for everyone and is easy to recreate.
It was the latter. Thanks for the clarification. If I ever decide to do another planted tank, I will consider following this advice/method.
I have a customer for whom I built a 70G sump for a planted tank, he was using a high rate dosing method along with and automatic water change system, I think it was called an overdosing method or something? Anyways not to derail this thread but his thread is here: http://www.plantedtank.net/forums/sh...d.php?t=165053 would you consider this a "doser" method you refer to in #1?
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote