Not sure about for a redfoot but I personally use an arcadia d3 combi lamp that provides heat and uv at the same time - they are expensive to buy but are guaranteed for 12 months and some tests have shown that they give out very good uv levels in excess of 2 years later. The other option is a heat source and separate uv tube the power needs can vary with species and I cant advise for a redfoot but Arcadia do some very good ones so maybe check their website