diff --git a/my_pyscf/fci/csf.py b/my_pyscf/fci/csf.py
index a6dba6d3..138fb87e 100644
--- a/my_pyscf/fci/csf.py
+++ b/my_pyscf/fci/csf.py
@@ -92,6 +92,10 @@ def make_hdiag_csf (h1e, eri, norb, nelec, transformer, hdiag_det=None, max_memo
         csd_offset = npair_csd_offset[ipair]
         det_addr = transformer.csd_mask[csd_offset:][:nconf*ndet]
         # mem safety
+        # Issue #54: PySCF wants "max_memory" on entrance to FCI to be "remaining memory". However,
+        # the first few lines of this function consume some memory, so that's difficult to
+        # implement consistently. "max_memory" here is currently the config parameter for the whole
+        # calculation.
         mem_remaining = max_memory - lib.current_memory ()[0]
         safety_factor = 1.2
         nfloats = nconf*ndet*ndet + det_addr.size 
@@ -284,6 +288,9 @@ def pspace (fci, h1e, eri, norb, nelec, transformer, hdiag_det=None, hdiag_csf=N
     safety_factor = 1.2
     nfloats_h0 = (npsp_det+npsp)**2
     mem_h0 = safety_factor * nfloats_h0 * np.dtype (float).itemsize / 1e6
+    # Issue #54: PySCF wants "max_memory" on entrance to FCI to be "remaining memory". However,
+    # the earlier lines of this function consume some memory, so that's difficult to implement
+    # consistently. "max_memory" here is currently the config parameter for the whole calculation.
     mem_remaining = max_memory - lib.current_memory ()[0]
     memstr = ("pspace_size of {} CSFs -> {} determinants requires {} MB, cf {} MB "
               "remaining memory").format (npsp, npsp_det, mem_h0, mem_remaining)
diff --git a/my_pyscf/mcscf/lasci.py b/my_pyscf/mcscf/lasci.py
index 072a0325..5c4f0bda 100644
--- a/my_pyscf/mcscf/lasci.py
+++ b/my_pyscf/mcscf/lasci.py
@@ -181,7 +181,6 @@ def get_grad_ci (las, mo_coeff=None, ci=None, h1eff_sub=None, h2eff_sub=None, ve
     for isub, (fcibox, h1e, ci0, ncas, nelecas) in enumerate (zip (
             las.fciboxes, h1eff_sub, ci, las.ncas_sub, las.nelecas_sub)):
         eri_cas = las.get_h2eff_slice (h2eff_sub, isub, compact=8)
-        max_memory = max(400, las.max_memory-lib.current_memory()[0])
         linkstrl = fcibox.states_gen_linkstr (ncas, nelecas, True)
         linkstr  = fcibox.states_gen_linkstr (ncas, nelecas, False)
         h2eff = fcibox.states_absorb_h1e(h1e, eri_cas, ncas, nelecas, .5)
diff --git a/my_pyscf/mcscf/lasci_sync.py b/my_pyscf/mcscf/lasci_sync.py
index 8934e30f..c64f5f46 100644
--- a/my_pyscf/mcscf/lasci_sync.py
+++ b/my_pyscf/mcscf/lasci_sync.py
@@ -263,6 +263,8 @@ def ci_cycle (las, mo, ci0, veff, h2eff_sub, casdm1frs, log):
                                                                       las.nelecas_sub, h1eff_sub,
                                                                       ci0)):
         eri_cas = las.get_h2eff_slice (h2eff_sub, isub, compact=8)
+        #max_memory = max(400, las.max_memory-lib.current_memory()[0])
+        # Issue #54: compute max_memory here, or in fcisolver?
         orbsym = getattr (mo, 'orbsym', None)
         if orbsym is not None:
             i = ncas_cum[isub]
@@ -288,6 +290,7 @@ def ci_cycle (las, mo, ci0, veff, h2eff_sub, casdm1frs, log):
 
         e_sub, fcivec = fcibox.kernel(h1e, eri_cas, ncas, nelecas,
                                       ci0=fcivec, verbose=log,
+                                      #max_memory = max_memory issue #54
                                       ecore=e0, orbsym=orbsym)
         e_cas.append (e_sub)
         ci1.append (fcivec)
diff --git a/my_pyscf/mcscf/lasscf_async/crunch.py b/my_pyscf/mcscf/lasscf_async/crunch.py
index 52978cbf..00fcb546 100644
--- a/my_pyscf/mcscf/lasscf_async/crunch.py
+++ b/my_pyscf/mcscf/lasscf_async/crunch.py
@@ -292,10 +292,11 @@ def casci_kernel(casci, mo_coeff=None, ci0=None, verbose=logger.NOTE, envs=None)
                            (mo_coeff.shape[1], casci.ncore, ncas))
 
     # FCI
-    max_memory = max(400, casci.max_memory-lib.current_memory()[0])
+    #max_memory = max(400, casci.max_memory-lib.current_memory()[0])
+    # Issue #54: count memory here, or in FCISolver?
     e_tot, fcivec = casci.fcisolver.kernel(h1eff, eri_cas, ncas, nelecas,
                                            ci0=ci0, verbose=log,
-                                           max_memory=max_memory,
+                                           #max_memory=max_memory,
                                            ecore=energy_core)
 
     t1 = log.timer('FCI solver', *t1)
diff --git a/my_pyscf/mcscf/mc1step_csf.py b/my_pyscf/mcscf/mc1step_csf.py
index c11dc311..5a5b81e8 100644
--- a/my_pyscf/mcscf/mc1step_csf.py
+++ b/my_pyscf/mcscf/mc1step_csf.py
@@ -58,9 +58,10 @@ def contract_2e(c):
     if mc.ci_response_space > 7:
         logger.debug(mc, 'CI step by full response')
         # full response
-        max_memory = max(400, mc.max_memory-lib.current_memory()[0])
+        #max_memory = max(400, mc.max_memory-lib.current_memory()[0])
+        # Issue #54: count memory here, or in fcisolver?
         e, ci1 = mc.fcisolver.kernel(h1, h2, ncas, nelecas, ecore=ecore,
-                                       ci0=ci0, tol=tol, max_memory=max_memory)
+                                       ci0=ci0, tol=tol)#, max_memory=max_memory)
     else:
         # MRH 03/24/2019: this is where I intervene to enforce CSFs
         fci = mc.fcisolver