The fertilator tells you how much to add: http://www.aquaticplantcentral.com/forum/fertilator.php.
Chuck Gadd's site helps you figure out how much to add. Just set the ml to 1 ml -- that will tell you how much solid fertilizer to add.Adding Calcium Carbonate: 1/2 tsp per 50 l / 13.2g of water will raise KH and GH level by 1 degree. I've heard (but not confirmed) that Calcium Carbonate dissolves very slowly, so it may be safe to add a bunch in at once, into your filter or something like that.
So for my fairly low-light (90W) 60g aquarium, I do a 50% water change once a week, and add 1-2 times a week. My target levels (from Tom Barr and Chuck Gadd):
Here's what I add:pH: 6.5 to 7.0 (use CO2 to reduce to this level) KH (hardness): 3-6 degrees GH (general hardness): 2-8 degrees NO3: 5ppm-10ppm Iron (Fe): 0.2ppm to 0.7ppm+ (but I'm not really doing this yet) PO4: 0.2ppm to 0.5ppm K: 20-30ppm Mg: 5-10ppm
Here's what Tom Barr recommends for a 20 gallon tank with high light and CO2:CaCO3: 4.5 tsp (only after water change) KNO3: 1/2 tsp (provides 7.56 ppm NO3 + 4.77 ppm K) KH2PO4: I figure you need very very little. 1/20 tsp provides .77 ppm PO4) K2SO4: 1.5 tsp - less necessary if you have a light fish load. (provides 17.79 ppm K) MgSO4: 3.5 tsp (Provides 8.24 ppm Mg)
You are simply better off using your eyes when dealing with how much trace you need. Keep the macro nutrienmts ina good range, then vary the milliliters of trace you add, say 5mls per 200 liters every 3 days, do that for a 3 weeks and note plant health. Then try 10 mls per 200 liters each 3 days and note plant health and so on.......... These ratios above will vary plant to plant. There is a range if you start at zero ppm and steadily increase concentration that is best for the plants. Below a range of NO3 of less or near 1-2ppm is typically too low, you want more for the plant to be happy. Above 15ppm or so is more than enough for the plant for a few days. What you do not want to do is to let the levels drop down to zero for more than a day or 1.5 days. Traces are fine, but the macro's you do not want this to occur longer than a 1-2 days. So what to do? Well do a large water change, find out if your source water has NO3 and PO4 in uit and how much. So if it's fairly clean, then you assume it to be zero ppm of PO4/NO3. Well if you do large frequent water changes, then your tank will have very very low levels of these, no tannins, no humics, no organic components and other things you do not test for. So you add KNO3, KH2PO4, K2SO4 and traces. After each water change you have a standard solution almost(well whatever of the % of the water changed will be referenced). Basically you do large weekly water changes to remove any excesses and re set the tank and then you estimate/guess the next 1-2 doses in the mid week. You can also "mega dose" right before a water change. This involves dosing 2-3x the PO4/NO3 about 24-12 hours before you do a large water change. The dosing prevents anything from running out while the large water changes prevent anything from building up. In this manner, one can maintain a good range of parameters without doing hardly any testing ever. pH should be monitored closely and KH/GH every so often. Other than that, not much else unless you are curious. You can see the DFW site: http://www.aquatic-plants.org/ Articles And www.sfbaaps.com "References"Glenn Attwood:
Matt Jarsky was accused of saying... (This is the Chelated Trace Mix from Homegrown Hydroponics, part of ther "Nutrient Six Pack.") I have noticed that Tom's dosing recommendations are always based on the use of a liquid trace mix. How much water should I mix with my powder to get a liquid trace mix of the concentration Tom uses in his dose recommendations? I have the same mix, and found the following helpful: http://www.thekrib.com/Plants/Fertilizer/dosing.html "If the concentration of Fe in the trace element. mix is 7 percent, then one gram of trace element powder added to 50 gallons of water is simply (0.07) x (5.3) = 0.37 ppm." I'm still going over it myself... time to haul out the ol' chemistry texts.Glenn Attwood:
I figured out the formula, this is based on making sure that one on the trace elements is correct (I would guess Fe most of the time) and letting the rest sort thems selves out. x = ((z/1000)y)/c where: x is # of grams of mix, z is your tank size in litres, y is the target ppm, and c is the concentration as percent. So for me to get .5ppm Fe in the 270 litres (75g tank is really 72g) from 7% Fe in the mix: x = ((270/1000).05)/0.07 x = 1.9g (which acording the Chuck Gadd's webpage is 1/3 teaspoon) If you think that this is incorrect, let me know.
PMDD assumes a PO4 limited tank is desirable and also at the same time a low Fe level is desirable. But a tank cannot have two limited nutients at once. Nor does "excess" Fe and PO4 cause algae in a well run tank. The testing of Fe and trying to keep a 0.1ppm residual just seems like a lesson in futility. Plants only need roughly 0.006ppm a day of iron, not much and beyond anything our test can come close to.