The new GH boost method is maintaining the dGH, but the Ca:Mg is high. I am restarting MgSO4 20 seconds (3.3 ml) per day. The concentrations of ++Ca and ++Mg derive from their respective dissolution rates. As long as MgCO3 and CaCO3 media are present in the flow path, both solutions will be constant in the effluent (determined by pH and flow rate). As a practical matter, the cation ratio cannot be readily adjusted through this method. Finding the correct supplementary dose of MgSO4 required to redress the deficiency will be a much easier experiment.
The KH and K are maintaining spot on, and have been for some time. The K2CO3/Alkaline Buffer mix and dosing rate are just right.
I have seen no effects so far of raising the pH. The one effect I would expect first might be appearance of algae, especially with the added light. Although the new lights have increased the oxygen tension to its normal elevated level, they are throttled to 75%. I will be interested to see the utilization rate of CO2 after a couple of months of this. The streaming water change regimen is holding the system in strict oligotrophy and the redox is exceptionally high. DOM, orthophosphate, and DIN are running very low. The plants are growing and have great color and there is no sign of algae as yet.
Today I am feeding fresh frozen and sinking green.
The Nymphaea has not bloomed in nearly a year. Today we have a flower.
Both the pads and the big, old swordplant leaves throw considerable shade. I trim the oldest and the most tatty. With the lillypad, I remove five or six at a time. This plant is prolific. It is constantly putting up new leaves, sometimes two or three at a time, and they grow FAST. To remain healthy, the plant needs a minimum of two mature floating leaves in order to conduct its vital gas balance. When I trim, I leave three or four. They are usually full grown and quite large, so there is still shade. Two things to bear in mind: 1) the plants being shaded, Java fern and crypts, are shade tolerant, and 2) the attenuation of the light discourages algae. When I do a major pruning, the surface really opens up. The tank is brighter then, and it has a different 'look', but shade sets in quickly as the large plants answer back. This is a kind of natural thing, and I also like the 'look' of the tank with life happening at the surface. The sag and hygro overspread and the sag and swords put out lots of flower runners. This is when we often see cherry barb fry.
Redox is unusually high. If I were running an ozonizer I would regard this as dangerous. The O2 in this system results from ordinary circulation and photosynthesis in the plants. The running average oxygen tension is 6.9 ppm, with a brief daily peak of 9.6 ppm (saturation) at 19:00. The ORP should gradually rise absent introduction of reducing organics, i.e. pollution sufficient to drive redox down; and if the stimulus conditions persist, a consistently high ORP should not be at all surprising. The principle stimulus conditions are rapid removal of autochthonous DOM (fresh turnover) and illumination that promotes robust carbon fixation with the resultant O2 generation. This ecosystem's oxidative potential is strictly "as results" from natural conditions; there doesn't appear to be much I could do about it. There are no strong oxidizers (peroxide, permanganate, ozone) present. Now on a more speculative note, I believe the ecosystem is responding on a profound level to the water change regime. The effects are multiple, gradual, subtle, and pervasive.
The GH, KH, micros, and potassium are stable at the present dosing and water change rates. While there is still some tweaking to be done, I am confident that the balance has been struck. I am very much okay with the pH at 6.8. The O2 cycle is ideal with the lighting where it is, there is no nuisance algae; plants, fish, and snails are happy. Interestingly, PO4 and NO3 are variable on a daily basis with no obvious correlation as yet to the feeding schedule.
Yesterday and today I fed fresh frozen, sinking green, and the usual flake. NO3 and PO4 have been trending low. Yesterday I manually added just a little KNO3 and KH2PO4 supplement. I have deleted two more ODEs: 12:00 and 00:00, and will feed more generously. As long as I can keep the redox up, heavier feeding is not a concern. Perhaps I am not seeing the patterns of nutrient fluctuations because I am feeding too lightly.
Today I am feeding fresh frozen, green sinking, and the usual flake. The past couple of days of more liberal feeding has seen the NO3 and PO4 return to more ideal levels. All of the parameters today are ideal.
The Nymphaea blossom lasted for two days and fairly quickly wilted. There is now a new flower head poking up at the surface. The Sagittaria are producing an abundance of little white flowers.
I must prune. It is getting dark in the jungle and looking congested. Also, the duckweed is back!
This AM out from the jungle pops this guy. This is an eel loach, Pangio sp, probably either anguillaris or doriae. I estimate its length now at 3.5 inches. It must have hitchhiked with my kuhliis when they were all tiny; that has been a few years ago.
Whatever has brought the kuhliis out into the open must have stirred this one as well. I hope to keep seeing all these loaches more now that they seem to have overcome their timidity. It sure is nice to get pleasant surprises like this.
The Nymphaea has bloomed again. Tuesday the flower head rose high above the waterline. Wednesday AM it opened. At 14:00 it had closed. It did the same today; opened early AM, closed early PM.
The Nymphaea flower did not open this AM. Tomorrow I will remove it and a couple of older pads as well.
Iron is declining just a little. I will bump up the Flourish Comprehensive ON time from 10 seconds to 15 seconds.
Potassium, GH, and KH remain stable. The dosing and the water changes are holding balance.
Orthophosphate and DIN are well controlled. In fact, I have been feeding liberally, including fresh frozen every day, and sinking green every other day, as well as twice daily flake, for the past ten days. I await upward movement in NO3 and PO4.
Because we will be getting a 72 hour stretch of temps above freezing beginning Tuesday, I will take the opportunity to hook up the garden hose one more time and service all the filters. Doing this means a big water change for the aquarium, so the parameters will see a reset.
The Glowlight Tetras, Hemigrammus erythrozonus, have decided to spend some quiet time up front, giving me the opportunity to show them off. This is a school of twelve. Their orange striping is intense. The males have brilliant white tips on their fins and are really gorgeous. I think they find their food and water suitable.
Yesterday was spent changing filters. The resulting water change was about 10%. All of the afternoon ODEs, and all of today's morning ODEs were stopped. Scheduled dosing went forward. Tonight I will do some manual tweaking.
All good except NO3. Nitrate has been coming in at 0 for quite awhile now with infrequent small bump-ups. After Tuesday's 10% water change I am certainly facing a deficiency condition, so I have added some KNO3 supplement. At this point I am closing out a month of charting NO3 and PO4. I have been feeding liberally, including fresh frozen every day for the last ten days. The two certain things are that 1) the nutrient that is present has been all autochthonous, deriving from the fish (i.e. fish food), and 2) the streaming water change regime is diurnally constant. There is sufficient variability in other environmental conditions that nutrient concentrations do fluctuate somewhat, but causality is obscure. Insofar as is concerned the idea that autochthonous nutrient is a sufficient source for the plants, the numbers are showing that orthophosphate persists in the system, but DIN does not. It may be necessary to supplement allochthonous KNO3 with daily dosing just enough that NO3 can be made to persist. I will add this manually for a time until I can get an idea of the appropriate dose rate.
In any case, I can state that generous feeding of the fish is possible without lapsing into a eutrophication trend.
The NeoMag and aragonite in pump loop #1 are supporting the GH. Upon opening the filters, I took the opportunity to double the NeoMag; I am interested to see if this will increase the Mg in the water column. I suspect supplementing MgSO4 will need to continue to keep a desirable Ca:Mg ratio, but we shall see.
I am still not seeing any problems with the pH increase. At the specified KH the CO2 ppm is in the mid-thirties. Except in the normal periphyton, which is very slow, there are no algae. Again, I attribute much of this to long-term maintenance of stable CO2, trophic status free from DOM, lean in nutrient, and rich in oxygen. I have the lighting pretty well turned up, and while there is benefit of shade from the canopy of large-leafed plants, I am not so leery as I used to be about the relationship between energy intensity and nuisance algae.