Eastleigh head to League Two opposition and might fancy their chances of an upset against Crewe.
Scott Rendell is bang in-form with seven in his last eight - the Spitfires have also lost just once at home since August.
Elsewhere in the FA Cup, Hartlepool get another shot at Exeter City.
The Pools have improved under Dave Challinor but the Grecians have won four of their last five outings.
There's also plenty of league action as AFC Fylde look to bounce back to Saturday's defeat at Barnet with a win over revitalised Sutton while Chesterfield are desperate for a win ahead of the visit of Yeovil Town to the Proact Stadium.
Managerless Kidderminster Harriers are looking to stop the rot on their travels - the Harriers head to Guiseley without an away win in six games.
They might still be top but Wealdstone have won just once in their last five games in all competitions - Eastbourne Borough are in town tonight.
Elsewhere, Chippenham Town head to Maidstone looking for their first win since early November.
Tuesday's FA Cup fixtures:
Crewe Alexandra v Eastleigh
Hartlepool United v Exeter City
Tuesday's National League fixtures:
AFC Fylde v Sutton United
Chesterfield v Yeovil Town
Tuesday's National League North fixtures:
Altrincham P-P Blyth Spartans
Guiseley v Kidderminster Harriers
Tuesday's National League South fixtures:
Hemel Hempstead P-P Weymouth
Maidstone v Chippenham
Wealdstone v Eastbourne Borough