Why is it advisable to use plastic fittings with plastic holding tanks?

Using plastic fittings with plastic holding tanks is advisable primarily due to the similar coefficient of thermal expansion. Different materials expand and contract at different rates when subjected to temperature changes. By using fittings made from the same material as the holding tank, you ensure that they will expand and contract at the same rate. This compatibility helps prevent stress and potential failure at the joints, ensuring a reliable and leak-free system.

Moreover, this alignment in thermal expansion reduces the likelihood of cracks or wear that could arise from the different expansion rates of dissimilar materials. Choosing materials that share this characteristic supports the overall integrity and longevity of the installation, particularly in environments where temperature changes can occur frequently.