Growmax Eco Grow 240 - 240 litres / hour - 2-Stage FilterGrowmax Water Filters Purer Water, for a Purer End Product! Growmax filtering systems remove a long list of chemicals from your tap water. If you're looking to grow medicinal grade herbs, then you're going to need to ensure that you're not adding unwanted chemicals to your nutrient regime. Contaminants often found in tap water are generally only found in low concentrations. However, over time, the concentrations of these contaminants can build up in