Choose and adjust a shrimp water-change routine

Choose water changes from the development of your tank, not a fixed percentage alone. Measure before and after maintenance, record the actual volume and check prepared replacement water. A small change with unsuitable water can be harmful; an insufficient change may leave a pollution problem unresolved.

What a change can dilute

Calculation example: starting at 20 mg/l of a fully dissolved substance with replacement water at 0 mg/l, a 10% change gives 18 mg/l after complete mixing; 50% gives 10 mg/l. This assumes no production, uptake or release during the change. These are calculation values, not advice that 20 mg/l is safe for a particular substance or species. In practice, substrate, food and animals may change the concentration again.

Make the routine measurable

• Choose a recurring checking and maintenance time. Record temperature, ammonia/nitrite when concerned, and relevant trends such as nitrate and conductivity. GH, KH and pH help assess composition.
• Prepare water using clean aquarium equipment. Check whether the utility uses chlorine or chloramine; treat where necessary with a suitable product according to its label. Prepare RO replacement water with the mineral product for your system.
• Use a thermometer. Treat TDS or conductivity as an additional check, not proof of identical minerals or absence of contamination.
• Siphon the planned amount, protect small animals and refill in a controlled way. Do not let equipment run dry and check operation afterward.
• Adjust volume or frequency if trends show accumulating waste or unintended water changes. Record your adjustment.

Top-ups are different

Evaporation leaves dissolved minerals behind; siphoning removes them. Topping up therefore does not replace water changes. For evaporation, choose water that avoids unwanted mineral accumulation, often pure RO water. Record evaporated and siphoned volumes separately, including in a Neocaridina tank.

An emergency does not follow the calendar

With detected ammonia/nitrite, likely contamination or several animals in distress, immediately investigate the source and how to reduce exposure. Do not wait for the scheduled day or for every possible contaminant to be measurable. Use suitable prepared clean water; repeating the change with the same suspect source may perpetuate the problem. Follow the emergency route in the water guide and investigate the change itself if signs began afterward.

This check remains necessary in planted aquariums. Plant uptake can change nutrient trends, but clear water or abundant greenery does not establish removal of every unwanted substance. Record fertiliser and major trimming alongside measurements. Do not automatically treat a fixed water-change schedule in a plant-product manual as a complete care plan for your shrimp.

Sources and scope

• SRAC 464: Interactions of pH, Carbon Dioxide, Alkalinity and Hardness
• CDC: Chlorine and chloramine in drinking water
• UF/IFAS: Ammonia in Aquatic Systems
• NDSU Extension: Electrical conductivity and TDS meters

Water-chemistry and nitrogen sources support measuring and dilution. The calculation assumes complete mixing and clean replacement water; it is not a recommended change percentage or safe concentration. The maintenance sequence is editorial advice.