Polder of Zuidland and Het Spui

Last Monday I filmed nearby Zuidland and Het Spui. I used a tripod for a more stable underground. I experienced several issues which I need to solve, like the need for ND (neutral density/gradient) filters to minimalize the effect of over exposure of some footage. So I am now looking around for Cokin filtersets/adapters/holders which I can put on my lenses. Hopefully this improves the contrast/exposure effects.