I also used to flood and drain via drip pies from the top (drain out the bottom)the whole block during light hours 3 times a day. It used to keep ph very stable. With the way the hugo blocks built and its size and gravity i found towards the top it would retain very slightly less water, so even when the block holds its maximum capacity of water the air to water ratio in the root level is right to keep the plant roots healthy. The way the blocks are built they will always hold enough air for proper growth. They cant be over watered as that air holding capacity is always there. But i found even if the block was totaly up to its max water holding capacity that constant regular watering would keep the ph stable, would flush out the old water and feed and renew it fresh. Would stop any salt build up too.