Great experiment . I love undergravel filter . Here is one main problem . if we don’t clean up the gravel while changing the water , with a gravel cleaner , the sediment accumulated more and more , and the final by products is , nitrates, phosphates , and others ,,, also the bicarbonate disappear , so the acidity of the water is high and the balance is off . Theses by products benefits mostly the algae and the plants start dying….
Thank you for watching. Detritus is dropped to the bottom level with an acrylic rod. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-G-4Kr8i2-yc.html Detritus accumulated in the bottom layer can be sucked out with an L-shaped pipe. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qAKkXurp6OU.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-MKo7VHXR5z8.html I feel that sucking out the detritus reduces the fertility of the shrimp, so I accumulate them for 546 days. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-fqjUViB5VxA.html