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As easy as it may sound, doing water change is one of the utmost important step in shrimp keeping. If you are able to maintain excellent water conditions, the rest of the elements on shrimp keeping should be fairly straight forward.
Purpose of water change
Why do we even change water? Well, the fastest and easiest way to remove large amount of Nitrate is through water change. Other methods such as having a good denitrification bacteria and plants to absorb the nitrate is good but some shrimp breeders have only a small amount of moss or plants in the tank.
Why the need to remove Nitrate
The reason for removal of Nitrate is although not harmful in small concentration <10ppm, higher potency of Nitrate is still harmful for the shrimp well being. As most of us use buffering soil, it releases Ammonia which converts to Nitrite and then to Nitrate, when both Ammonia and Nitrite is 0 it means the tank is well established and cycled, and leaving Nitrate to be manually remove.
If Nitrate is not remove in a consistent basis, the concentration will keep going up and after 3-4 months the Nitrate level might be way over the top and you do a 20% water change, you start seeing Shrimps die. Why? Although the shrimp might have ‘got use’ to the higher levels of Nitrate but when the fluctuation of pure water hits the tank, it creates a vacuum to be filled (Not just Nitrate but other water parameters). Then why do we even need to change water, can’t we just leave it alone? Eventually, the Nitrate and other water parameters will catch up to the shrimp ability to adapt, it is highly dependent on what type, how many shrimps and for how long.
The common practice is about 10-15% weekly depending on stocking level and i would always start off with 10% weekly for lower stock tanks and less stable breed and 15% for higher stock tanks and more stable breed.
My mistakes during water change Or Points to note:
Like everyone, i make mistakes too and they can be costly mistakes and one of the more critical mistake i try not to make again is to be less distracted during water change. I have flooded my shrimp tank area a few times because i was doing something else and the float valve failed me.
Another mistake that i have made is a faulty TDS meter giving me different reading. Now i measure and confirm my TDS meter with another meter that is of the same batch and manufacturing date. I have gone through many TDS meter from cheap to expensive ones, i find that as long as it’s from a reputable water treatment company it is ok. Nowadays i don’t purchase TDS meters from Aquarium shop as there is no one that can i go back to when there is an error.
Delaying change of Resin. It can get messy i know, all the small resin bits, the need to dispose them after but i generally change them at 800 – 1000 litres or 6 months whichever comes first. Resins in a grand scheme of things is not something you can save and although some resins are expensive it is better to error on the side of changing it then to leave it and have problems later.
Another point to note is the flow rate of the pure water going in the tank or from reservoir. Some like to hold the water in a reservoir some do it direct from the DI machine, whichever way, more sensitive shrimp will be affected by the speed of the pure water inflow. For example, i can do direct high speed pure water injection into a PRL or PBL tank but for a Black fancy tank i’ll have to slowly drip them in. Why? Reason is simple, the quick sudden change injection of pure water like rain works for stronger more stable breeds but for more sensitive ones they’ll never be found in the wild nor they be able to adapt to it. Hence, it is important to know your shrimp well and slowly but surely let the water infuse into the tank water column. After which, reminerize and measure your TDS again.
TDS is not everything, it just measure the total dissolved solids. Please do measure other parameters, especially for sensitive shrimp.
Last but not least for those using sponge either sponge filter or sponge laid in UGF, please do note that the wool type will clog up eventually, do not wait till your shrimps start dying one by one and blame it on the water, it actually is the sponge that is releasing back or not being able to absorb anymore from the water column (it will still operate as is). wash or change them, i think the max a sponge can go without issue is about 8 months but i wouldn’t even recommend that time frame. For UGF sponge usage, i use a coarser type as i prefer them over the wool ones since they will not degrade or clog up faster than the wool type.
My Routine
Fairly simple, 10% all tanks weekly. No top up during the week. TDS 80-90, i’m always gearing towards 85-90 as a tighter band gives me more control of what the issues are. I personally do direct TDS 0 water into the tanks except for Neocaridina where i use tap water direct. Normal PRL i do use tap water direct as well, we have good water here in Singapore.
Every 6 months, i will vacuum the soil to remove the ‘dust’ from the ADA soil in the UGF section.
That’s about it! Thanks for reading.
Sharing my messy wet area for all water change activity.
Would you be willing to write more about UGFs for part of the tank? Why do UGF? Why part of the tank only? How long do you go before you need to change the substrate in the UGF? Could you use a big box filter or box UGF to provide the same benefits?