Despite all the advice to the contrary, I tried out some Caridina shrimp in the tapwater-based Shrimphaus. This did not go well and after 3 weeks there was only one brave survivor left. The usual way to keep soft water shrimp is to start with reverse-osmosis (RO) water which is selectively remineralised mostly to restore […]
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Evidence-based systematic investigation using experiment, scientific literature, and/or first principles to explain and predict outcomes.
An interesting and widely misunderstood concept is the distribution of carbonate species (DIC: dissolved inorganic carbon) in an aquarium. What you usually see is a form of Bjerrum plot where it looks very much like the amount of dissolved CO2 goes to zero as the pH gets much higher than 7. Where this goes wrong […]
Read more →Cambridgeshire has hard, alkaline tap water. A number of iron salts such as iron phosphates and hydroxides are essentially insoluble. This can potentially cause issues with lack of iron availability for plants in an aquarium. In both the Fireplace Aquarium and the Shrimphaus, modified estimative index fertilising provides plenty of phosphates, and the alkaline tap […]
Read more →In a high alkalinity low-tech (non-CO2 injected) aquarium like the Shrimphaus there is a significant amount of potential carbon dioxide locked away and mostly unusable by plants in the form of bicarbonate. High alkalinity also means high pH, both of which are reputedly bad for aquarium plants. In theory, you can solve both problems – […]
Read more →The carbonic acid / bicarbonate / carbonate buffering system is very important in an aquarium and largely controls both the pH and the resistance to change of the pH in the water. These three carbonate-based species can all interconvert in a connected equilibrium reaction: (1) H2CO3 (carbonic acid) ⇌ H+ + HCO3– (bicarbonate) ⇌ 2H+ […]
Read more →Absent active interventions such as injecting CO2 gas, having an ‘active substrate’ and the metabolic processes of fish and plants, the pH of an aquarium will equilibrate to a level mostly determined by the alkalinity of the water – the amount of externally supplied bicarbonate and carbonate ions. In most cases, “externally supplied” means came […]
Read more →NOTE: if you want to be really super-serious about measuring alkalinity you could consider instead the upgrade to this page: ‘Measuring low levels of alkalinity‘ The pH of water in an aquarium is a measurement of the concentration of hydronium ions H3O+ (or just H+ for short). Neutral water has a pH of 7, and […]
Read more →Shrimphaus is [was] usually around pH 8.2 The Shrimphaus has an equilibrium pH of around 8.2 which is on the alkaline side. Chemistry and geology of Cambridgeshire water makes this the case, discussed below. Later note: Neocaridina can do ok in higher pH water, but Caridina not so much Chalk aquifers mean hard, alkaline water […]
Read more →A drop checker is a simple and reliable device for measuring the level of dissolved CO2 in aquarium water. The drop checker hangs from the wall of the tank inside the tank and completely underwater, e.g. with a suction cup, and contains a liquid with a pH indicator dye in the “drop” portion which is […]
Read more →“Estimative Index” aquarium plant fertiliser method and strategy The ‘estimative index’ (EI) is a fertilizer concept originated by Tom Barr where the general idea is to never have plant nutrients be limiting in the water column. Plants will grow and generally outcompete algae (so the theory goes). In practice, while I’m sure the outcompeting part […]
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